o 


GIFT  OF 


BIOLOGY 


A  Balance-Chemograph 


And  the  Excretion  of  Carbon  Dioxide  During  Rest 

and  Work. 

A  Dissertation  Submitted  to  the  Faculty  of  the    De- 
partment of  Literature,  Science  and  the  Arts 
of  the 

UNIVERSITY  OF  MICHIGAN 


In  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of 

DOCTOR  OF  PHILOSOPHY 

fey 
GEORGE  OSWIN  HIGLEY,  M.  S.  '93 

Instructor  in  Chemistry,  University  of  Michigan 

ANN  ARBOR,  MICHIGAN, 
MAY,  1905 


A  Balance-Chemograph 

And  the   Excretion  of  Carbon  Dioxide  During  Rest 

and  Work. 

A  Dissertation  Submitted  to  the   Faculty  of  the  De- 

partment of  Literature,  Science  and  the  Arts 

of  the 

UNIVERSITY  OF  MICHIGAN 

In  Partial  Fulfillment  of  the  Requirements  for   the 

Degree  of 

DOCTOR  OF  PHILOSOPHY 


GEORGE  OSWIN  HIGLEY,  M.  S.  '93 

Instructor  in  Chemistry,  University  of  Michigan 

ANN  ARBOR,  MICHIGAN, 
MAY,  1905 


s 


Preface 


This  work  was  done  in  the  physiological  laboratory  of  the  Univer- 
sity of  Michigan.  The  writer  desires  to  express  his  thanks  to  Profes- 
sor Warren  P.  Lombard  for  his  continued  and  active  interest  in  this 
research;  to  Professors  S.  L.  Bigelow  and  Victor  C.  Vaughan  for  valu- 
able suggestions;  to  Mr.  W.  P.  Bowen  in  conjunction  with  whom  the 
work  of  Sections  III.,  VI.,  and  a  portion  of  VII.  was  done;  and  finally 
to  friends  who  have  so  kindly  served  as  subjects. 

The  work  outlined  in  these  papers  was  carried  out  with  the  Higley 
and  Bowen  respiration  apparatus  described  in  an  article  published  in 
the  American  Journal  of  Physiology,  Volume  XII,  4,  page  311.  (1904.) 


TABLE  OF  CONTENTS 


I.  Introduction. 

II.  The  Balance-chemograph. 

1.  Construction. 

2.  Tests. 

3.  Uses. 

III.  Methods  of  Determining  the  Rate  of  Excretion  ol  Carbon  Di- 
oxide from  the  Lungs. 

1.  Methods  Previously  Employed. 

a.  Respiratory  Chamber  Methods. 

b.  Mask  and  Mouth-piece  Methods. 

2.  Method  Employed  in  this  Research. 

IV.  The  Relation  of  Carbon  Dioxide  Excretion  to  Body  Weight. 

1.  Introduction. 

2.  Method. 

3.  Results. 

V.  Influences  which  Modify  the  Rate  of  Carbon  Dioxide  Excre- 
tion during  Rest. 

1.  Introduction. 

2.  Method. 

3.  Results. 

VI.  The  Excretion  of  Carbon  Dioxide  during  Uniform  Muscular 
Work  and  its  Relation  to  the  Secondary  Rise  of  the  Pulse  Rate. 

1.  Method. 

2.  Results. 

VII.  The  Latent  Period  of  Carbon  Dioxide  Excretion. 
1.     Method. 

2     Results. 

3.  Conclusions. 
General  Summary. 


293412 


A  NEW  CHEMOGRAPH  AND  SOME  OF  ITS  PHYSIOLOGICAL 
APPLICATIONS 

1.     Introduction. 

The  graphic  method  dates  from  the  invention  of  the  Kymograph 
by  Carl  Ludwig  in  1847.  The  superiority  of  this  method  over  any  meth- 
od which  involves  the  observing  and  recording  of  a  series  of  phenome- 
na by  a  single  observer  is  obvious.  "The  graphic  record  includes  more 
than  can  be  grasped  by  any  observer  no  matter  how  well  trained.  The 
records  being  preserved  and  read  repeatedly,  the  chance  of  error  is 
greatly  reduced.  Time  relations  can  be  worked  out  on  a  graphic  re- 
cord with  a  precision  which  can  not  be  approached  by  direct  observa- 
tion." Applied  first  in  the  study  of  the  character  of  complex  cardiac 
and  respiratory  movements  this  method  soon  found  numerous  appli- 
cations in  the  hands  of  the  physiologist,  the  physicist  and  the  engineer. 
It  was  not  until  recently,  however,  that  the  chemist  seriously  turned 
his  attention  toward  a  similar  application  of  this  method  to  a  study 
of  the  course  of  chemical  reactions. 

In  1899  Ostwald1,  while  engaged  in  an  investigation  of  the  re- 
markable behavior  of  chromium  towards  acids,  was  led  by  the  great  ex- 
penditure of  time  required  to  note  at  frequent  intervals  the  indications  of 
a  gasburette,  to  devise  an  apparatus  which  should  record  automatically 
the  rate  of  evolution  of  hydrogen  .  The  gas  was  caused  to  flow  from  the 
generator  through  a  long  capillary  tube,  a  pressure  thus  being  pro- 
duced approximately  proportional  to  the  rate  of  evolution  of  the  gas. 
This  pressure  was  caused  to  actuate  a  light  lever  by  means  of  an  ordi- 
nary tambour,  and  the  curve  of  rate  of  solution  of  the  metal  was  thus 
recorded  upon  a  strip  of  paper.  With  this  apparatus  (the  original 
chemograph)  Ostwald  demonstrated  the  periodic  character  of  .'he 
chemical  action;  the  effect  upon  the  reaction  of  changes  of  temperature, 
and  of  concentration  of  acid;  the  effect  of  numerous  reagents  on  the  pe- 
riodicity of  the  action;  and  the  synchronism  of  changes  in  the  rate  of 
chemical  action  with  those  of  the  electrical  tension  of  the  metal.  A 
consideration  of  Ostwald's  paper  leads  to  the  conviction  that  the  graph- 
ic method  alone  could  have  yielded  such  satisfactory  results  in  the 
study  of  a  problem  of  this  kind. 

So  far  as  the  writer  was  aware  when  this  research  was  begun,  no 
successful  attempt  had  ever  been  made  to  determine  the  rate  of  a  chem- 
ical change  by  recording  the  movements  of  a  balance  beam.  However, 
in  March,  1904,  Professor  G.  N.  Stewart,  of  Chicago  University,  while 
examining  the  apparatus  to  be  described  in  this  paper,  stated  that  he 
had  some  time  previously  demonstrated  the  change  in  weight  of  a  dialy- 
zer  filled  with  cane-sugar  solution  and  suspended  from  the  arm  of  a 
balance  in  a  solution  of  pure  water.  By  means  of  a  lever  attached  to 


the  arm  of  the  balance,  a  curve  of  change  of  weight  of  the  dialyzer  was 
recorded  upon  a  drum.  Professor  Stewart's  paper  was  read  at  a  meet- 
ing of  the  Chemical  Society  of  Owens  College,  Manchester,  England,  but 
was  published  only  by  title. 

The  idea  of  securing  a  continuous  record  of  the  carbon  dioxide  ex- 
haled from  the  lungs  by  recording  the  movement  of  a  balance,  was  sug- 
gested by  Prof.  W.  P.  Lombard  as  a  possible  means  of  explaining  the 
changes  in  the  pulse  rate  resulting  from  muscular  work.  Bowen2  had 
found  that  in  all  vigorous  work  there  are  two  well  marked  stages  of 
increase  in  pulse  rate,  which  are  often  separated  by  a  period  of  uni- 
form rate.  First,  there  is  an  immediate  and  rapid  rise,  the  primary 
rise,  and  later  a  more  gradual  secondary  rise.  The  primary  rise  oc- 
curs so  promptly  after  the  beginning  of  work  (latent  period  .8  of  a  sec- 
ond), that  it  could  not  be  caused  by  the  direct  action  of  waste  pro- 
ducts on  the  heart  centers.  The  secondary  rise,  however,  which  be- 
gins, with  the  most  vigorous  work  done  in  the  research  (852  Kilogram 
metres  per  minute)  one  minute  and  twenty  seconds  after  the  beginning 
of  work,  might  have  been  caused  by  the  direct  inffuence  upon  the 
heart  of  some  waste  product.  The  discovery  of  Loewy3  that  tartaric 
acid,  introduced  into  the  jugular  vein  of  an  animal,  markedly  increas- 
es the  respiratory  volume,  seemed  to  indicate  that  acid  waste  products 
thrown  into  the  blood  during  the  work  might  also  be  the  cause  of  the 
secondary  rise  in  pulse  rate  noted  by  Bowen.  One  of  these  acid  waste 
products,  carbon  dioxide,  was  looked  upon  as  a  possible  cause  of  the 
phenomenon  mentioned.  It  was,  therefore,  believed  that  a  graphic  re- 
cord of  the  changes  in  rate  of  excretion  of  this  substance,  placed  by  the 
side  of  the  curve  of  the  pulse  rate- might  throw  light  on  the  cause  of 
the  change  of  the  latter  and  could  not  fail  to  be  of  interest. 


II.     THE  BALANCE-CHEMOGRAPH 

*T;~. 

1.     Construction. 

The  apparatus  for  absorbing  carbon  dioxide  and  recording  upon 
a  blackened  paper  its  rate  of  flow,  is  constructed  as  follows:  (Fig.  1,  El- 
evation). It  consists  of  a  Ruprecht  lecture-room  balance,  capable  of 
carrying  a  load  of  6  kilograms  in  each  pan  and  of  turning  to  5  milli- 
grams. To  the  beam  there  was  attached  a  copper  tube  one  and  one- 
half  centimeters  in  diameter  as  shown  by  figure  2.  Dry  air  contain- 
ing carbon  dioxide,  enters  at  A  through  a  short  piece  of  very  thin  rub- 
ber tubing  made  of  a  surgeon's  finger  cot,  passes  through  the  portion 
designated  by  the  arrows  to  the  end  of  the  beam  and  downward 
through  two  rubber  connections  like  that  just  mentioned,  and  a  glass 
tube  D  (Fig.  1)  to  the  chamber  for  the  absorption  of  carbon  dioxide. 

—5— 


FIGURE  1. — This  figure  represents  an  elevation  of  thechemograph.  The  air  enters  at  A 
and  takes  the  direction  shown  by  the  arrows.  C  is  the  absorbing  apparatus,  and  C' 
the  counterpoise.  Four  gram-weights  are  placed  upon  the  left  beaker,  and  the  lever- 
points  thereby  deflected  upwards  on  the  drum  (I).  The  curve  of  carbon  dioxide  ab- 
sorbed in  C,  is  written  downward  to  the  right  upon  the  drum. 


FIGURE  2.— A  horizontal  section  through  the  beam  and  balance  tubes.    The  air  passes 
through  those  portions  only  which  are  designated  by  arrows. 


suspended  upon  the  arm  of  the  balance.  (C  Fig  1.)  From  the  ab- 
sorption apparatus  the  air  passes  upward  through  similar  connections 
to  the  balance-tube  C,  back  on  the  opposite  side  of  the  balance-beam 
to  the  center,  where  it  leaves  the  balance  through  another  piece  of  rub- 
ber tubing,  and  then  passes  into  guard  tubes  G'  and  G",  which  will  be 
described  later. 

Absorption  apparatus.  (C,  Fig  1).  Several  forms  of  absorption 
apparatus  have  been  used  in  connection  with  the  chemograph.  That 
constructed  for  use  in  work  experiments  has  been  most  employed  and 
will  be  described  here. 

Since  there  was  a  question  of  removing  the  carbon  dioxide  from 
air  flowing  at  the  rate  of  30  litres  per  minute  during  work,  the  absorp- 
tion apparatus  is  necessarily  large.  It  consists  of  a  beaker  20  centi- 
metres in  diameter  at  the  top,  and  50  centimetres  deep,  with  cover  of 
thin  copper,  provided  with  openings  two  centimetres  in  diameter,  into 
which  are  fitted  the  inlet  and  outlet  tubes.  The  air  passes  downward 
into  the  beaker  through  a  thin  glass  tube  2  centimetres  in  diamoler, 


to  within  about  2  centimeters  of  the  bottom  of  the  beaker,  ending  In 
an  open  space  3  centimeters  deep  and  of  a  diameter  equal  to  that  of 
the  beaker.  (This  open  space  was  left  because  it  was  thought  that  the 
carbonic  acid  gas  would  thereby  be  more  uniformly  distributed  through- 
out the  whole  cross-section  of  absorbent  placed  above.)  The  air  now 
rises  through  about  5  kilograms  of  coarse,  carefully  screened  soda-lime, 
and  then  through  glass-wool  covered  with  phosphorus  pentoxide  to  hold 
back  dust  and  the  last  trace  of  water  formed  in  the  reaction.  This 
beaker  when  charged  weighs  about  5%  kilograms.  It  is  counterpoised 
by  another  beaker  of  the  same  exterior  volume  filled  with  spent  soda- 
lime. 

Recording  Apparatus.  In  order  to  record  the  movements  of  the 
balance,  there  is  attached  to  the  end  of  the  balance-beam  a  steel  loop 
which  engages  the  short  arm  of  the  light  lever  (E,  Fig  1),  made  of  two 
.straws  placed  side  by  side  and  tipped,  at  the  short  end,  with  a  steel 
wire,  and  at  the  long  end  with  a  piece  of  parchment  paper.  By  meajis 
of  an  arrangement  (F,  Fig.  1)  which. will  be  clear  from  the  figure,  the 
fulcrum  of  the  lever  may  be  adjusted  vertically,  transversely,  and  hor- 
izontally. On  the  short  arm  of  the  recording  lever  (40  millimetres  in 
length)  there  is  placed  a  movable  weight,  by  an  adjustment  of  which 
the  long  arm  (350  millimetres  in  length)  is  made  to  slightly  preponder- 
ate. The  lever  records  upon  the  drum  the  movements  of  the  balance- 
beam  magnified  nine  times.  Since  much  depends  upon  the  accurate  ad- 
justment of  the  writing  lever  upon  the  paper,  the  kymograph  is  set 
upon  a  base  provided  with  ball-bearings  and  with  two  springs  working 
against  a  screw,  so  that  the  kymograph  may  be  rotated  around  a  ver- 
tical axis  and  thus  the  drum  be  quickly  and  accurately  adjusted  to  the 
recording  lever  at  any  time.  Attached  to  the  frame  of  the  kymograph 
is  a  vertical  brass  rod  to  which  are  clamped  three  slender  brass  springs 
which  extend  horizontally  and  whose  points  may  be  brought  into  light 
contact  with  the  paper  on  the  drum.  The  middle  one  marks  the  level 
of  the  center  of  the  fulcrum  of  the  recording  lever.  This  marker 
when  once  adjusted  is,  of  course,  never  disturbed.  The  upper  and  low- 
er ones  draw  lines  marking  the  upper  and  lower  limits  of  the  excur- 
sion of  the  lever-point  during  calibration.  They  are  readjusted  from 
time  to  time  as  may  be  necessary. 

It  has  been  already  stated  that  the  rubber  connections  of  the  bal- 
ance were  made  very  light  in  order  to  avoid,  as  far  as  possible,  inter- 
ference with  the  free  movements  of  the  balance.  In  order  now  to  be 
able  to  write  a  curve  of  considerable  length,  representing,  for  example, 
a  mass  of  five  grams,  it  became  necessary  to  diminish  by  some  means 
the  sensibility  of  the  balance  while  interfering,  as  little  as  possible, 
with  the  uniformity  of  its  movement.  There  was,  therefore,  attached 
to  the  frame  of  the  balance,  about  ten  centimetres  from  the  central 
knife-edge,  a  steel  yoke  (H,  Fig.  1)  passing  over  the  beam.  From  this 
yoke  there  was  suspended  a  coil,  five  centimetres  in  length  and  about 


one  centimeter  in  Diameter,  made  of  phosphor-bronze  wire  .83  millime- 
tres in  diameter.  This  coil  was  attached  at  its  lower  end  to  the  upper 
side  of  the  beam  of  the  balance  by  means  of  a  hook,  which  together 
with  the  yoke  could  be  set  at  any  desired  distance  from  the  central 
knife-edge.  A  set  screw,  with  a  check-nut  by  which  the  upper  end  of 
the  coil  is  attached  to  the  yoke,  admits  of  an  adjustment  of  the  tension 
of  the  spring  at  the  will  of  the  operator. 

Adjustment  of  tension. — The  balance  is  brought  into  equilibrium 
with  spring  disconnected.  The  spring  is  now  attached  to  the  beam 
and  brought  into  a  state  of  tension  by  turning  the  screw  at  the  upper 
end  of  the  coil,  after  which  weights  are  placed  upon  the  pan  on  the 
same  side  until  equilibrium  is  again  restored.  In  most  of  the  work 
done  with  this  apparatus  the  spring  has  had  an  initial  tension  of  four 
grams. 

We  have  here  a  combination  of  the  beam  and  the  spring  balance. 
This  apparatus  was  subjected  to  a  series  of  careful  tests  in  order  to 
ascertain  whether  the  records  inscribed  by  it  upon  the  blackened  pa- 
per were  of  any  value. 

Tests  of  the  balance:  1.  Calibration.  A  careful  test  was  made  of 
the  amount  of  vertical  deflection  of  the  end  of  the  recording  lever  on 
the  blackened  drum  produced  by  a  mass  of  five  grams.  This  was  done 
as  follows:  The  balance  was  brought  into  equilibrium.  The  beam  was 
now  arrested  and  five  gram-weights  were  placed  upon  the  counterpoise 
beaker;  this  produced  an  angular  deflection  of  the  beam  of  about  1  de- 
gree 45  minutes,  and  a  vertical  deflection  of  the  recording  lever-point 
of  about  73  millimetres.  After  a  delay  of  about  30  seconds  to  allow 
the  lever  to  assume  its  position  of  rest,  the  screw  controlling  the  posi- 
tion of  the  drum  was  carefully  turned  until  the  blackened  paper  was 
brought  into  light  contact  with  the  writing  lever,  and  the  kymograph 
was  started  and  allowed  to  run  until  a  short  horizontal  line  had  been 
drawn  by  the  point  of  the  recording  lever  upon  the  paper.  The  beam 
was  now  arrested,  the  weights  removed,  the  beam  again  released,  and 
the  writing  lever  again  allowed  to  come  into  a  position  of  equilibrium. 
The  kymograph  was  now  started  as  before  and  a  second  light  horizon- 
tal line  drawn  upon  the  paper.  The  vertical  deflection  of  the  writing 
point  is  a  measure  of  the  mass  of  five  grams.  This  process  was  repeat- 
ed many  times,  the  weight  being  alternately  added  and  removed  to 
find  out  the  accuracy  with  which  the  point  of  the  writing  lever  returned 
to  the  same  level  as  the  drum.  It  was  found  that  at  the  beginning  of 
work,  after  the  apparatus  had  stood  for  some  hours,  there  was  some 
irregularity  at  the  first  two  or  three  movements  of  the  beam.  However, 
after  a  few  minutes  the  movements  became  quite  uniform.  Starting, 
now,  from  the  highest  position  of  the  recording  lever,  the  gram 
weights  were  removed,  one  by  one,  the  position  of  rest  of  the  point  of 
the  lever  being  marked  at  each  step  by  a  short  horizontal  line  as  in 
the  preceding  case. 


X    X 


FIGXJRES  3A  and  3B  show  the  results  of  calibration  of  the  chemograph  with  5  gram- 
weights.  The  distances  XX'  are  the  vertical  deflections  of  the  recording-lever  point 
for  a  mass  of  5  grams  added  to  the  pan,  The  numbers  represent  the  vertical  deflec- 
tion, in  millimetres,  of  the  lever  point  for  ONE  gram.  A  calibration  of  at  least  one 
series  is  made  at  the  beginning  of  each  experiment  and  often  at  the  close  also. 


TABLE  I   (A). 


Millimetres.  Millimetres.  Millimetres.  Millimetres. 

Series  I.  Series  II.  Series  III.  Average. 

Upper  gram   15.4  15.1  14.7  15.06 

Second  gram    15.3  15.0  15.0  15.1 

Third  gram 15.2  15.3  14.7  15.1 

Fourth  gram 14.6  14.6  14.7  14.63 

Fifth  gram (14.2)  (13.9)  (13.3) 

Total  deflection  .              ..60.5  60.0  59.1 


TABLE  I   (B). 

Series  I.       Series  II.  Series  III.  Average. 

Millimetres.  Millimetres.  Millimetres.  Millimetres. 

Upper  gram  14.4                  14.7  14.7  14.6 

Second  gram    15.1                  14.8  15.0  15.03 

Third  gram 14.8                  14.8  14.5  14.7 

Fourth  gram  14.7                  14.6  14.5    .  14.6 

Fifth  gram    ....(14.0)                (14.5)  (14.4) 

Total  deflection  .              ..59.0                  58.9  58.7 


Fig.  3  A  and  Table  I  A  show  the  results  of  one  of  these  calibrations 

—9— 


in  which  are  given  the  deflections  due  to  one  gram.  Omitting  the  low- 
er or  fifth  gram  of  each  in  A,  we  have  the  following  averages.  15.06 — 
15.1 — 15.1 — 14.6.  The  total  deflection  for  four  grams  is,  in  the  three 
series,  60.5,  60,  and  59.1  millimetres,  respectively.  The  extreme  varia- 
tion in  deflection  for  the  four  grams  is  1.4  millimetres  or  2.3  per  cent, 
and  the  greatest  variation  from  the  average  of  0.7  millimetres,  or  1.35 
per  cent.  The  greatest  variation  in  deflection  for  a  single  gram  (omit- 
ting the  lower  or  fifth  gram  in  each  series)  is  0.8  millimetres  or  5.2  per 
cent.;  the  greatest  variation  from  the  average  is  0.36  millimetres  or  2.4 
per  cent.  Figure  3  (B)  and  Table  I  (B)  show  the  results  of  a  calibra- 
tion of  the  same  apparatus,  with  slightly  different  tension  in  the  spring. 
In  this  case  the  greatest  variation  in  deflections  for  4  grams  and  1  griim 
are  0.3  millimetres  or  0.5  per  cent,  and  0.6  millimetres  or  4  per  cent., 
respectively,  and  the  greatest  variation  from  the  average,  0.2  millime- 
tres or  3.2  per  cent.,  and  .38  millimetres  or  2.5  per  cent.  The  results 
of  numerous  calibrations  shou  ing  that  the  deflection  fcr  the  lower  or 
fifth  gram  invariably  gives  low  values,  the  use  of  this  portion  of  the  arc 
has  been  discontinued. 

2.  Test  with  a  weighed  quantity  of  mercury. — A  small  crystall- 
izing dish,  previously  weighed  upon  a  fine  balance,  was  placed  upon 
the  right  beaker,  and  the  balance  brought  into  equilibrium.  Four  gram 
weights  were  now  added  to  the  left  beaker  and  the  point  of  the  lever 
thereby  deflected  vertically  upward  about  58  millimetres  upon  the 
drum.  The  usual  calibration  with  4  grams  having  now  been  made,  the 
drum  was  started  and  a  slow  stream  of  mercury  was  allowed  to  flow 
into  the  crystallizing  dish  from  a  simple  apparatus  with  capillary  de- 
livery tube.  There  was  thus  described  upon  the  drum  a  short  horizon- 
tal line,  followed  by  a  more  or  less  regular  curve  inclining  downward 
toward  the  right.  Finally  when  about  two  grams  of  mercury  had  be  on 
allowed  to  flow  in  this  manner  into  the  crystallizing  dish,  the  addition 
of  mercury  was  discontinued,  and  the  curve  caused  to  end  in  a  horizon- 
tal line.  The  beam  was  now  arrested  and  the  crystallizing  dish  re- 
moved. The  vertical  deflections  of  the  writing  lever  due  to  the  suc- 
cessive addition  and  removal  of  four  grams  in  the  initial  calibration 
process  were  now  determined.  The  average  of  these  values  is,  of 
course,  the  graphical  equivalent  of  four  grams.  From  this  there  waa 
readily  obtained  the  modulus  of  the  balance,  viz.:  the  number  of  milli- 
grams represented  by  one  millimetre  of  vertical  distance  upon  the 
drum.  The  vertical  distance  between  the  initial  and  final  positions  of 
the  writing  lever  in  the  experiment  with  mercury  was  now  measured, 
and  the  weight  of  mercury  added  obtained  by  multiplying  the  modulus 
by  this  value.  Finally  the  crystallizing  dish  with  its  contents  was  re- 
weighed  upon  a  fine  balance,  and  the  weight  of  mercury  thus  deter- 
mined compared  with  that  obtained  by  the  graphical  method. 


—10— 


TABLE  II. 


Showing  the  results  of  calibration  of  Balance  with  Mercury. 


Vertical 
deflecti'n 
for  one 
gram 

* 

Modulus 
M 

Initial 
height  of 
writing 
point 

—  h. 

Final 
height 
of 
writing 
point 
rh' 

Weight 
graphi- 
cally 
deter- 
mined 
(h.h')M 

Weight 
on 
fine 
balance 

Error 

Per 
cent. 
Error 

Millime- 
tres 
11.63 

0.0859 

Millime- 
tres 
82.5 

Milli- 
metres 
55.9 

2.287 

2.273 

+  0.014 

+  0.61 

11.63 

0.0859 

55.9 

26.4 

2.537 

2.5695 

—0.0326 

—1.26 

11.63 

0.0859 

83.0 

58.5 

2.148 

2.1624 

-0.0144 

—0.66 

11.63 

0.0859 

58.5 

34.6 

2.055 

2.0707 

—0.0152 

—0.70 

14.57 

0.0686 

88.0 

66.9 

1.447 

1.4331 

+0.014 

+0.98 

14.57 

0.0686 

66.9 

34.5 

2.2237 

2.2172 

+0.0065 

+0.29 

14.57 

0.0686 

87.8 

59.9 

1,9149 

1.9092 

+0.0057 

+0.3 

14.57 

0.0686 

59.9 

24.3 

2.4434 

2.4424 

+0.001 

+0.04 

14.58 

0.0686 

88.0 

76.0 

0.823 

0.847 

—0.024 

—2.8 

14.59 

0.0686 

76.0 

62.3 

0.9396 

0.9282 

+0.0114 

+1.23 

14.59 

0.0686 

73.3 

59.3 

0.953 

0,9488 

+0.0031 

+0.40 

14.59 

0.0686 

59.3 

42.7 

1.139 

1.177 

—0.0213 

—1.9 

*Experiments  1-4  were  made  by  the  use  of  a  brass  spring;  the  fo!1owing  experiments 
with  a  phosphor-bronz  spring  of  quite  a  different  tension.  This  accounts  for  the  widely 
different  values  of  the  modulus. 


The  results  of  a  series  of  such  tests  are  shown  in  Table  II,  in 
which  there  are  given:  Vertical  deflection  in  millimetres  of  the  lever- 
point  for  one  gram  added  to  the  pan:  Modulus  (M)  or  the  weight  in 
grams  corresponding  to  one  millimetre  deflection;  initial  height  of 
writing  lever-point  "h";  Final  height  of  lever-point  h';  weight  of 
mercury  as  graphically  determined,  (h-h')  M;  Weight  of  mercury  as 
determined  on  fine  balance.  Error  +  or  — ,  and  per  cent  of  error.  It 
will  be  observed  that  the  error  was  generally  positive,  and  varied  in 
the  different  experiments  between  .001  and  .0326  grams,  the  average 
error  being  about  .014  grams,  or  approximately  .7  per  cent. 

3.  Test  with  uniform  current  of  Carbon  Dioxide. — It  will  thus  be 
seen  that  the  working  of  the  chemograph  is  more  uniform  and  accu- 
rate when  the  weight  is  added  gradually  as  in  the  case  of  the  mercury 
and  without  arresting  the  motion,  that  when  the  weights  are  added  a 
gram  at  a  time  with  the  necessary  arrest  of  the  beam.  It  was  now 
thought  desirable  to  test  the  character  of  the  curve  written  by  the  lever 
as  the  result  of  a  practically  constant  addition  of  weight  to  the  absorp- 
tion apparatus.  Accordingly  a  current  of  carbon  dioxide,  as  uniform  as 
possible,  was  caused  to  flow  for  «even  minutes  through  the  apparatus, 
the  drum  meanwhile  revolving  uniformly.  The  result  was  a  smooth 

—11— 


curve  about  30  centimetres  in  length,  which  was  a  very  close  approxi- 
mation to  a  straight  line,  measurements  showing  that  at  no  point  was 
the  deviation  from  a  straight  line  greater  than  .7  millimeters.  This 
experiment  was  repeatedly  performed  with  practically  the  same  re- 
sult. 

It  is  evident  that  when  the  recording  lever  has  reached  the  lower 
limit  of  the  arc,  the  beam  may  be  arrested,  and  additional  weights  add- 
ed without  interrupting  the  experiment  and  with  a  loss  of  only  a  small 
portion  of  the  curve.  This  may  be  repeated  for  hours,  enabling  the  op- 
erator to  determine  both  the  course  of  the  reaction  throughout  its  whole 
extent  and  the  total  weight  of  gas  absorbed. 

The  method  of  determining  the  rate  of  the  reaction  during  any  pe- 
riod is  as  follows:  With  a  radius  equal  to  the  length  of  the  long  arm  of 
the  recording  lever,  and  with  the  proper  points  on  the  central  reference 
line  as  centres,  arcs  are  drawn  cutting  the  time  line  at  the  beginning 
and  the  end  of  the  desired  period,  and  also  the  curve  of  carbon  dioxide. 
The  vertical  distance  between  the  two  intersections  of  the  carbon-diox- 
ide curve  by  these  arcs  is  the  measure  of  the  amount  of  that  gas  ab- 
sorbed during  the  time  cut  off  below.  The  modulus  of  the  apparatus 
having  been  determined  as  described  earlier,  the  rate  of  absorption  be- 
tween the  desired  limits  is  readily  determined. 

4.  Test  with  a  weighed  quantity  of  carbon  dioxide. — A  series  of 
experiments  were  now  carried  out  with  carbonic  acid  gas.  There  was 
set  up  a  carbon  dioxide  apparatus  consisting  of  a  small  fractionating 
flask  provided  with  a  dropping  funnel  and  delivery  tube,  to  which  was 
attached  a  drying  tube  filled  with  pumice  stone  and  sulphuric  acid. 
Into  this  flask  there  was  brought  a  quantity  of  a  saturated  solution  of 
sodium  carbonate,  while  sulphuric  acid  was  placed  in  the  dropping  fun- 
nel. The  apparatus  was  now  carefully  weighed,  after  which  it  was  at- 
tached to  the  drying  tube  of  the  chemograph,  a  current  of  pure  air 
free  from  carbon  dioxide  was  drawn  through  it  at  the  rate  of  half  a 
litre  per  minute,  and  the  sulphuric  acid  was  slowly  dropped  upon  the 
carbons *e.  The  gas  thus  produced,  diluted  with  seven  litres  per  min- 
ute of  purified  outer  air  was  drawn  through  the  absorption  apparatus 
of  the  chemcgraph,  the  kymograph  drum  meanwhile  revolving  at  a 
uniform  rate.  This  experiment  was  repeatedly  tried,  with  the  follow- 
ing results. 

No.  Weight  Carbon  Dioxide. 

By  Loss  in  Weight.  Graphically.         Error.     Per  Cent  Error. 

1.  2.4  2.33  .07  2.9 

2.  3.548  3.487  .061  1.7 

3.  1.810  1.815  .004  0.03 

4.  2.933  2.83  .103  3.5 

5.  3.152  3.192  .040  1.2 

—12— 


3     Uses. 

It  is  evident  that  this  form  of  chemograph  may  be  used  in  a  study 
of  the  course  of  many  chemical  reactions  in  which  gas  or  vapor  is 
evolved,  since  the  apparatus  will  evidently  write  a  curve  of  loss  in 
weight  as  readily  as  of  gain  in  weight.  It  is  only  necessary  to  pTace 
the  generator  upon  the  pan  of  the  balance,  to  make  the  usual  adjust- 
ments, and  allow  the  process  to  continue  as  long  as  desired.  A  tracing 
of  the  course  of  a  reaction  in  which  there  is  an  escape  of  hydrogen 
will,  perhaps  not  be  practicable  with  this  apparatus,  on  account  of  the 
lightness  of  that  gas.  However,  the  curves  of  rate  of  loss  of  water, 
ammonia,  carbon  dioxide,  etc.,  may  be  readily  written. 

III.  METHODS  OF  DETERMINING  THE  RATE  OF  EXCRETION 
OF  CARBON  DIOXIDE  FROM  THE  LUNGS. 

1.     Methods  Previously  Employed. 

A  great  variety  of  methods  have  been  employed  by  different  investi- 
gators to  determine  the  rate  of  excretion  of  carbon  dioxide  from  the 
lungs.  The  methods  are  of  two  types:  Respiratory  Chamber  Meth- 
ods and  Mask  or  Mouth  Piece  Methods. 

a.     Respiratory  Chamber  Methods. 

The  earliest  form  of  respiratory  chamber  was  a  simple  bell  jar  in 
which  a  small  animal  was  confined,  in  some  cases  until  asphyxiation 
resulted.  Samples  of  the  inclosed  air  were  taken,  as  desired  during 
the  course  of  the  experiment  and  at  its  close,  and  analyzed  for  carbon 
dioxide  and  oxygen.  Such  a  method  was  made  use  of  by  Black4. 
Priestly5  Lavoisier  and  La  Place6,  r-nd  others.  It  has  recently  been 
successfully  employed  by  Haldane  and  Smith6  in  a  study  of  the  ques- 
tion of  existence  of  odorous  sutstances  in  the  air  exhaled  by  a  human 
subject.  This  method  is,  of  course,  open  to  the  objection  that  there 
is  a  constant  diminution  in  the  amount  of  oxygen  present  in  the  cham- 
ber, and  a  correspcnding  increase  in  respiration  products  v.ith  dis- 
turbance of  the  normal  respiratory  exchange.  In  order  to  remove  the 
objectionable  features  of  this  primitive  apparatus,  Lavoisier  suggested 
two  improvements  which  resulted  in  the  development  of  two  distinct 
forms  of  respiratory  chamber  which  are  in  use  at  the  present  time.  In 
the  first  form,  that  of  Regnault  and  Reiset,  the  air  of  the  chamber  is 
circulated  by  means  of  pumps  through  a  system  of  purifying  tubes 
charged  with  concentrated  sulphuric  acid  and  with  potassium  Hydrox- 
ide for  the  removal  of  water  and  carbon  dioxide  respectively;  the  oxy- 
gen is  brought  up  to  the  normal  amount  by  addition  of  a  fresh  supply 
from  a  gasometer  and  the  air  returned  to  the  chamber.  This  apparatus 
has  been  employed  in  a  modified  form  by  Hoppe-Seyler  and  Stroganow' 
Pfluger  and  Colesanti8.  and  Atwater  and  Benedict9. 

Lavosier's  second  modification  WP.S  developed  by  Scharling10.  An 
animal  was  placed  in  a  chamber  consisting  of  a  large  cask,  provid- 

—13— 


ed  with  inlet  and  outlet  tubes.  Air  freed  from  carbon  dioxide  was 
drawn  through  the  chamber,  the  moisture  and  carbon  dioxide  in  the 
out-going  air  being  absorbed  by  concentrated  sulphuric  acid  and  po- 
tassium hydroxide  respectively.  Samples  of  the  air  in  the  cask  at  the 
beginning  and  the  end  of  the  experiment  were  also  taken  and  analyzed. 

Since  it  w^as  found  difficult  to  maintain  a  sufficient  ventilation  and 
at  at  the  same  time  to  secure  complete  absorption  of  carbon  dioxide  and 
water,  Pettenkofer11  modified  this  apparatus  in  the  following  man- 
ner: The  total  volume  of  air  drawn  through  the  chamber  was  deter- 
mined by  means  of  a  meter.  Continuous  samples  of  the  air  entering 
and  leaving  the  chamber  were  also  taken,  measured,  and  analyzed  for 
carbon  dioxide  and  water;  the  difference  in  the  content  of  carbon  diox- 
ide and  wrater  in  the  two  sample's  multiplied  by  the  ratio  of  the  total 
ventilation  to  the  volume  of  the  samples,  gave  the  amount  of  carbon  di- 
oxide and  water  exhaled  by  the  subject. 

Pettenkofer's  apparatus  was  further  improved  by  Tigerstedt12, 
was  given  a  capacity  of  100  cubic  metres,  and  has  since  been  extensive- 
ly employed  by  Johannsen13,  Atwater  and  others.  This  apparatus 
has  many  points  of  excellence  some  of  which  are  as  follows: 

(1)  It  admits  of  experiments  of  indefinite  length. 

(2)  It  admits  of  making  experiments  upon  eighteen  or  more  per- 
sons at  once,  thus  enabling  the  experimenter  to  obtain  average  values. 

(3  In  its  most  complete  form  as  employed  by  Atwater14,  it 
performs  the  wrork  both  of  a  respiration  apparatus  proper  and  of  a  ca- 
lorimeter, giving  results  which  are  comparable  in  accuracy  to  those  ob- 
tained by  the  use  of  the  combustion  calorimeter  and  the  combustion 
furnace. 

Quite  recently  there  has  appeared  a  respiratory  chamber  method 
by  Jacquet15.  In  respect  to  capacity  of  chamber  there  is  here  a  de- 
parture from  modern  methods,  as  it  holds  only  two  or  three  cubic  me- 
ters. However,  the  samples  of  air,  taken  at  intervals  of  one  hour,  are 
collected  over  mercury,  and  analyzed  by  the  very  accurate  Petterson 
and  Hogland  method  thus  permitting  a  determination  of  oxygen  as 
well  as  carbon  dioxide. 

(b)     Mask  and  Mouthpiece  Methods: 

The  first  quantitative  study  of  the  respiration  was  made  with  the 
Mask  method  by  Lavoisier16.  This  investigator  in  1790,  read,  before 
the  French  academy,  a  paper  in  which  a  new  method  was  described. 
The  subject  wore  a  mask  (tete  du  cuivre)  connected  with  a  gasometer 
containing  air.  This  air  after  passing  into  the  lungs  of  the  subject 
was  exhaled  through  a  huge  tube  filled  with  caustic  potash  solution, 
the  increase  in  weight  of  which  represented  the  carbon  dioxide. 

Method  of  Speck17.  According  to  this  method  the  subject,  with 
closed  nostrils,  breathes  through  a  mouth-piece  from  a  spirometer, 
the  air  being  collected  in  a  second  spirometer.  At  the  close  of  the  ex- 
periment a  sample  of  air  is  drawn  from  the  expiration  spirometer  and 

—14— 


its  percentage  of  carbon  dioxide  and  of  oxygen  determined  by  absorp- 
tion with  barium  hydroxide  and  pyrogallol  respectively. 

Method  of  Geppert  and  Zuntz18.  According  to  this  method  the 
expired  air  is  forced  through  a  carefully  calibrated  gas  meter  and  its 
volume  accurately  measured.  Samples  of  the  air  are  taken  by  means 
oi  a  special  sampling  device  which  is  operated  by  the  gas-meter  itself. 
A  number  of  tubes  each  with  a  capillary  at  the  upper  end,  are  filled  to 
the  tips  with  acid  water.  These  are  connected  to  a  lowering  device 
which  is  driven  by  a  belt  running  over  a  pulley  on  the  main  axis  of 
the  gas-meter.  As  the  air  passes  through  the  gas-meter  the  pulley  re- 
volves, the  leveling  tube  connected  with  the  collecting  apparatus  is 
gradually  lowered  and  the  collecting  tube  is  thus  filled  with  air,  whose 
composition  has  been  found  to  represent  quite  accurately  that  of  the 
air  passing  through  the  meter.  These  samples  of  air  are  then  analyzed 
for  carbon  dioxide  and  oxygen,  and  there  is  thus  obtained  both  the  car- 
bo  ndioxide  excreted  and  the  oxygen  absorbed,  giving,  of  course,  the 
respiratory  quotient. 

Method  of  Hanriot  and  Richet19.  The  method  of  these  investiga- 
tors is  beautiful  in  principle.  The  outside  air  is  drawn  through  an  ac- 
curately caibrated  gas-meter,  is  then  inspired  by  the  subject  and  ex- 
pired through  a  second  gas-meter.  It  now  passes  through  an  absorp- 
tion apparatus  charged  with  concentrated  potassium  hydroxide  solu- 
tion which  dissolves  the  carbon  dioxide,  after  which  it  is  measured  by 
a  third  gas-meter.  If  v  represents  the  volume  of  inspired  air,  v1  that  of 
the  expired  air,  and  v"  that  of  the  expired  air  deprived  of  carbon  di- 
oxide, it  is  evident  that  v1  minus  v11  represents  the  volume  of  carbon 
dioxide  excreted,  and  v  minus  v11  represents  the  volume  of  oxygen 
absorbed. 


2.     Method  Employed  in  This  Research. 

Each  of  the  methods  outlined  above  has  its  excellent  features  and 
has  contributed  to  our  knoweldge  of  the  respiration  process;  however, 
as  a  careful  study  showed  no  one  of  them  to  be  adapted  to  a  determin- 
ation of  the  rate  of  change  of  carbon  dioxide  excretion,  within  short 
intervals  of  time,  such  as  was  demanded  in  this  research,  Mr.  "W.  P. 
Bowen  and  the  writer20  devised  the  apparatus  now  to  be  described. 

The  subject  breathes  through  a  mask  with  valve-chamber  for  the 
separation  of  the  inspired  and  expired  air.  The  latter  is  dried  by 
means  of  sulphuric  acid,  and  is  then  freed  from  carbon  dioxide  by  pass- 
ing through  the  chemograph  as  described  in  a  preceding  section.  The 
air  now  passes  in  succession  through  two  guard-tubes  and  a  gasometer 
and  to  a  suction  pump.  The  apparatus,  which  with  the  exception  of 
mask,  chemograph  and  pump,  is  shown  in  figure  4,  is  constructed  in 
the  following  manner: 

Mask.     The  subject  respires  through  a  mask  made  as  follows:  A 

—15— 


copper  wire  2  millimetres  in  diameter  is  so  bent  as  to  fit  over  the 
bridge  of  the  nose  and  the  face,  inclosing  nose  and  mouth.  A  piece  of 
heavy  tin  is  then  bent  in  the  same  form,  that  of  an  ovoid  about  11  cen- 
timetres in  length  and  8  centimetres  broad  at  the  widest  part.  This 
is  soldered  to  the  wire,  making  the  sides  of  a  box  about  4  centimetres 
in  depth  and  rather  closely  fitting  the  face.  The  space  between  this 
edge  and  the  face,  is  made  air-tight  in  the  following  manner:  A  rubber 
tube,  such  as  is  used  on  the  Townshend  ether  inhaler,  is  stretched  on 
over  the  wired  edge  and  fastened  with  cement.  By  inflating  the  tube 
and  closing  it  off  by  means  of  a  clamp,  a  cushion  filled  with  air  is 
brought  between  the  face  and  the  wired  edge  of  the  mouth  piece.  A 
sheet  of  rubber  is  stretched  over  the  front  of  the  box,  and  firmly  ce- 
mented and  wired  in  place.  This  is  then  pierced  in  the  center  and 
through  it  passes  a  short  glass  tube  1.2  centimeters  in  diameter,  which 
is  attached  to  the  valve-chamber.  Especial  care  was  taken  to  make 
the  volume  of  the  tubes  between  the  mouth  and  the  valves  as  small  as 
possible.  The  mask  is  held  firmly  to  the  face  by  wide  elastic  bands 
passing  around  the  head. 

Valve-chamber:  (V,  Fig.  4).  The  valve-chamber  is  of  the  same 
general  form  as  that  used  by  Zuntz  and  S'chumburg",  except  that  it 
is  made  of  glass  instead  of  metal,  thus  permitting  a  view  of  the  work- 
ing of  the  valves.  It  consists  of  a  large  T  tube,  20  centimetres  in  length 
and  4  centimetres  in  diameter,  with  a  side  tube  1.2  centimetres  in  di- 
ameter, to  which  the  mouth  piece  is  attached.  The  valve  seats  are 


JFf] 


FIGURE  4. — The  respiration  apparatus  except  ni'sk,  chemograph  and  pump.  Out-door 
air  eaters  at  O.  R  is  the  bag.  The  dryiag  apparatus  and  guard  tube  are  shown  at 
G.  A  and  B  connect  with  the  tubes  of  the  chemograph  T  is  an  auxiliary  tube  with 
adjustable  valve,  by  means  of  which  the  flow  of  air  through  the  main  circuit  may 
be  regulated. 


—16— 


of  cork  covered  with  thin  sheet-rubber  fastened  on  with  rubber  ce- 
ment. The  openings  are  about  1.5  centimetres  in  diameter;  the  valves 
are  made  of  thin  sheet-rubber  stiffened  above  with  a  disk  of  very  thin 
aluminum  foil  attached  by  means  of  rubber  cement.  The  out-door  air 
enters  the  lower  end  of  the  valve-chamber  through  a  wide  glass  tube. 
(0). 

From  the  valve-chamber  the  air  passes  into  a  rubber  balloon  hold- 
ing when  moderately  distended  about  3  litres.  At  each  expiration  this 
balloon  is  somewhat  inflated,  but  is  deflated  through  the  chcmograph 
by  the  action  of  the  pump  during  the  next  inspiration.  There  is  thus 
a  substantially  uniform  delivery  of  air  to  the  chemograph. 

It  is  often  convenient  to  cause  the  expired  air  to  pass  for  a  time  di- 
rectly to  the  pump  without  passing  through  the  chemograph.  For  this 
purpose  a  shunt  is  introduced  in  the  main  circuit  beyond  the  balloon. 

Drying  Tubes.  The  apparatus  for  the  removal  of  moisture  con- 
sists, essentially,  of  a  U  tube  75  centimetres  in  length  and  4  centimetres 
interior  diameter,  filled  with  coarse  pumice  stone  saturated  with  con- 
centrated sulphuric  acid.  This  tube  is  followed  by  a  guard  tube  (G  Fig. 
4),  about  25  centimetres  long,  filled  in  the  same  manner.  The  com- 
pleteness of  the  action  of  the  preceding  tube  may  be  seen  in  the  fact 
that  the  guard  tube  in  no  case  gained  more  than  .01  grams,  and  usually 
less  than  ,005  grams,  during  an  experiment  in  which  air  saturated 
with  water  vapor,  and  flowing  at  the  rate  of  30  litres  per  minute,  pass- 
ed through  the  train  for  30  minutes. 

From  the  guard  tube  the  air  flows  through  the  absorption  beaker 
of  the  chemograph,  passing  then  through  two  guard  tubes  G'  and 
G"  filled  with  pumice  stone  and  sulphuric  acid.  The  first  of  these 
tubes  in  an  ordinary  work  experiment  shows  a  gain  of  only  .05  grams; 
the  weight  of  the  second  remains  practically  unchanged.  The  air  pass- 
es now,  at  the  will  of  the  operator,  through  a  shunt  tube  containing 
clear  lime-water  as  a  test  for  the  presence  of  carbon  dioxide,  then 
through  an  Elster  gas-meter  and  to  the  pump. 

Suction  Pump.  In  order  to  relieve  the  lungs  of  the  subject  from 
the  labor  involved  in  forcing  the  expired  air  through  the  tubes  and  gas- 
meter,  the  latter  is  connected  to  the  suction  side  of  a  number  2  Amer- 
ican blower,  capable  of  drawing  air  through  the  entire  apparatus  at 
the  rate  of  30  litres  per  minute.  This  amount  of  air  is  sufficient  for  a 
subject  engaged  in  moderate  muscular  work,  but  its  rate  of  flow  is  not 
equal  to  that  at  which  air  passes  trom  the  lungs  during  a  vigorous  act 
of  expiration.  The  balloon  previously  mentioned  is  introduced  in  the 
circuit  in  order  to  permit  the  subject  to  exhale  freely,  the  air  expelled 
at  one  expiration  being  drawn  from  the  balloon  by  the  pump  during 
the  next  inspiration. 

It  has  already  been  stated  that  the  suction  pump  is  capable  of 
drawing  30  litres  of  air  per  minute  through  the  respiration  apparatus. 
Since,  however,  in  rest  experiments  the  subject  needs  only  6  to  8  litres 

—17— 


of  air  per  minute,  some  system  of  regulation  was  needed  whereby  the 
amount  of  air  drawn  through  the  apparatus  could  be  adjusted  at  will. 
There  was  therefore  introduced  above  the  gasmeter  a  side  tube  (T  Pig. 
4)  provided  with  an  adjustable  valve.  When  this  valve  is  closed  there 
is  drawn  through  the  train  the  amount  of  30  litres  per  minute;  when 
the  valve  is  open  the  resistence  of  the  short  side  tube  is  so  slight  that 
little  or  no  air  passes  through  the  train.  The  handle  of  the  valve  pass- 
es over  a  graduated  arc.  A  preliminary  calibration  process  enables 
the  operator  to  so  set  the  valve  that  any  desired  volume  of  air  up  to  30 
litres  per  minute  will  pass  through  the  train. 

Some  of  the  advantages  claimed  for  this  respiration  apparatus  are 
the  following: 

(1)  As  a  result  of  the  excellent  fit  of  the  mask  and  of  the  relief 
afforded  to  the  respiratory  organs  by  the  combination  of  balloon  and 
suction  pump,  the  conditions  approach  very  closely  to  those  of  normal 
respiration.     In  fact,  it  has  several  times  happened  that  a  subject  has 
fallen  asleep  during  a  rest  experiment,  after  the  mask  had  remained 
continuously  upon  the  face  for  from  one  to  three  hours. 

(2)  This  method  permits  of  a  determination  of  the  carbon  dioxide 
excreted  during  normal  respiration  within  2  per  cent. 

(3)  This  method  obviates  the  necessity  of  taking  samples  of  the 
expired  air,  and  of  making  long  and  tedious  analyses  followed  by  com- 
plicated calculations.     At  the  close  of  an  experiment  lasting  an  hour 
or  more  the  total  weight  of  carbon  dioxide  excreted  by  the  subject  may 
be.  ascertained  in  five  minutes  or  less. 

(4)  By   reason   of  the  capacity   of  the   chemograph   to   register 
changes  in  rate  of  absorption  of  carbon  dioxide,  the  whole  course  of  ex- 
cretion can  be  determined. 


IV.     THE  RELATION  OF  CARBON  DIOXIDE  EXCRETION  TO 
BODY  WEIGHT. 

1.     Introduction. 

Considerable  work  has  already  been  done  in  this  field  by  Zuntz" 
Johanssen23,  Magnus-Levy24,  Tigerstedt  and  Sonden25  and  others. 
The  average  results  given  in  the  form  of  carbon  dioxide  excretion  per 
kilogram  of  body  weight  per  minute  are  widely  variable,  as  will  appear 
by  reference  to  Table  III. 

—18— 


TABLE  III. 
Showing  the  Relation  of  Carbon  Dioxide  Excretion  to  Body  Weight. 


Carbon  Dioxide 

Conditions  of  Experiment.  -  Excretion  Observer, 

Grams  per  Kilogram 
and  minute. 

1.  Complete  rest  in  bed;  average  for  24 

hours 0048  Johansson. 

2.  Complete  rest,  sitting;  average  for  24 

hours 00516  Johansson. 

3.  Complete  muscular  rest 00512  1 

.00484  j  Zuntz' 

4.  Ordinary  rest  in  bed,  average  for  24 

hours 00578  Johansson. 

5.  Complete     muscular     rest     reclining 

from  9:35  a.  m.  to  7:21  a.  m 0058  Magnus-Levy. 

6.  Complete  muscular  rest,  fasting 00594  Magnus-Levy. 

7.  Nine  persons  sitting  quietly,  10  a.  m.  Tigerstedt 
until  3  p.  m .00792  and  Sonden. 

8.  Five  persons  doing  no  muscular  work;  Tigerstedt 
average  fasting  value 00756  and  Sonden. 

9.  Nineteen  persons  muscular  rest,  reclin- 
ing, 3:20  to  5:30  p.  m..: .0063  Higley. 


These  variations  arise  partly  because  the  subjects  during  the  ex- 
periments were  in  different  degrees  of  muscular  rest,  and  partly  be- 
cause the  experiments  were  made  at  various  lengths  of  time  after 
meals,  thus  involving  the  variable  work  of  the  digestive  organs.  The 
great  difference  between  the  carbon  dioxide  excretion  during  absolute 
rest  and  during  merely  relative  rest  has  been  well  shown  by  Johanssen. 
These  experiments  in  which  Johanssen  himself,  was  the  subject,  were  in 
part  carried  out  while  the  subject  was  in  the  state  or  ordinary  rest 
in  bed  and  in  part  while  all  muscular  tension  was  avoided  as  far  as 
possible.  In  the  former  experiments  the  average  carbon  dioxide  ex- 
cretion per  kilogram  of  body  weight  per  minute  was  .0059  grams;  in 
the  latter  series  the  average  was  only  .0054  grams,  a  difference  of  8.6 
per  cent.  The  posture  of  the  subject  also  has  a  great  influence  on  the 
intensity  of  the  gaseous  exchange.  Thus  Johanssen  found  the  carbon 
dioxide  excretion  while  the  subject  was  sitting,  to  be  1.5  grams  per 
hour  more  than  while  he  was  reclining,  a  difference  of  7%.  Katzen- 
stein  has  observed,  in  parallel  work,  a  difference  of  from  12  to  22% 
for  this  difference  of  posture. 


—20— 


The  experiments  of  Vierordt26,  Speck27,  and  others  have  sho\vn 
that  the  rate  of  excretion  of  carbon  dioxide  is  increased  40  per  cent  as  a 
result  of  the  digestion  process.  This  increase  is  attributed  to  the  in- 
crease of  work  of  the  body  due  to  the  increased  activity  of  the  digestive 
organs,  and  also  in  part  to  conversion  of  carbohydrates  into  fats 
with  separation  of  a  large  percentage  of  the  oxygen  of  the  former  as 
carbon  dioxide  (Hanriot  2S).  From  these  results  it  follows  that  a  uni- 
form rate  of  excretion  of  carbon  dioxide  per  kilogram  of  body  weight 
in  the  case  of  a  number  of  subjects  or  even  with  the  same  subject  can 
not  be  expected,  unless  the  experiments  are  carried  out  at  approximate- 
ly the  same  hour,  and  at  about  the  same  length  of  time  after  a  meal 
which  is  approximately  the  same  as  to  amount  and  character. 

A  number  of  persons,  mainly  medical  students,  having  volunteered 
to  act  as  subjects,  the  writer  carried  out  experiments  on  the  rate  of 
excretion  of  carbon  dioxide  per  kilogram  of  body  weight. 

It  is  not  claimed  that  the  experiments  now  to  be  described  wero 
carried  out  in  an  ideal  manner,  since  the  subjects  were  under  the  con- 
trol of  the  experimenter  only  during  the  20  minutes  immediately  pre- 
ceding the  experiment.  Furthermore,  in  most  cases  the  subjects  had 
had  no  previous  experience  in  similar  work.  However,  the  experi- 
ments were  carried  out  at  approximately  the  same  time  of  day,  the 
subjects  partook  of  their  midday  meal  at  about  the  same  hour,  and  the 
work  of  the  subjects  was  about  the  same  during  the  hours  that  inter- 
vened between  the  meal  and  the  experiment.  The  subjects  were  engag- 
ed for  the  most  part  in  Physiological  laboratory  work  during  the 
hours  that  intervened  between  the  pj  eceding  meal  and  the  experiment. 
All  the  subjects  were  apparently  in  good  health  except  that  two  were 
troubled  at  the  time  with  indigestion  and  two  had  colds. 

(2)  Method.     The  experiments  were  conducted  as  follows:   Each 
subject  in  turn  reclined  upon  a  couch  for  about  15  minutes  preceding 
the  beginning  of  the  work.     The  mask  was  now  adjusted  and,  at  the 
end  of  a  further  period  of  5  m'nutes  the  experiment  began.     Great 
pains  were  taken  that  the  subject  should  be  in  a  state  of  as  complete 
muscular  rest  as  possible. 

(3)  Results.     The  results  are  shown  in  table  IV  in  which  are  giv- 
en: sex;  age;  weight  of  subject  (exclusive  of  clothing)  in  pounds  and 
kilograms;  date;  time  elapsed  since  preceding  meal;  length  of  experi- 
ment; carbon  dioxide  excretion  in  grams  per  minute,  and  in  grams  per 
minute  per  kilogram  of  body  weight;  remarks. 


—11— 


TABLE  IV. 
Table  Showing  Relation  of  Body  Weight  to  Carbon  Dioxide  Excre- 


tion: 


No 

Weight 
without 
.  Sex  Age  Clothing        Date 

Ibs      Kilos  Mo.  Day  Hr. 

Time  H,ength     Carbon     PerMin.  & 
Since  of    Ex-    Dioxide     Kilo  Body 
Preced  perim't  Excretion      Weight          Remarks 
ing    Minut's  Per  Min.       Grams. 
Meal                    Grams. 

1 

M 

23 

135 

61  5 

3    7 

3  50 

3.5hrs.     10 

.400 

•  0065 

2 

M 

167 

76 

3    7 

4.20 

4 

10 

•  393 

.0056 

Adipose  tissue 

3 

M 

20 

137 

62-2 

3    9 

4-40 

4  25 

10 

•  377 

•  C06 

4 

M 

20 

3    9 

5-00 

4-75 

10 

-348 

5 

M 

21 

137 

62-2 

3  14 

4.00 

4 

6 

-410 

•  0065 

6 

M 

20 

126 

57-3 

3  14 

4-20 

4 

7 

.420 

•  0073 

7 

M 

20 

139 

63-2 

3  14 

5-20 

5 

7 

417 

(.0066) 

Catarrh  infec'n 

8 

F 

30 

107 

49 

3  16 

4.15 

4 

8 

.297 

•  006 

9 

F 

19 

112 

51 

3  16 

4.45 

4.5 

6 

.341 

.0067 

10 

F 

30 

176 

580 

3  16 

5  30 

5-20 

6 

.442 

-0'>55 

Adipose  tissue 

11 

M 

20 

33 

60.2 

3  18 

4.00 

3-75 

4 

-366 

•  0061 

12 

M 

21 

115 

52-3 

3  18 

4-15 

4 

3 

.283 

-0054 

13 

M 

22 

145 

66 

3  18 

4.30 

4 

5 

.503 

(.0076) 

Nausea 

14 

M 

21 

162 

73-6 

3  19 

3-20 

3 

6 

.465 

.0063 

15 

M 

27 

190 

86.4 

3  19 

3-20 

3-5 

5 

-552 

.0064 

16 

M 

22 

129 

58 

3  19 

4-00 

3 

5 

.368 

.0063 

17 

M 

25 

15* 

71-6 

3  19 

4.00 

3-5 

= 

549 

.0076 

18 

M 

24 

135 

561.2 

3  21 

3-50 

3-5 

5 

.376 

•  0061 

19 

M 

26 

154 

570 

3  21 

4.00 

3-5 

7 

-463 

(.00f6) 

Slight  nausea 

20 

M 

26 

1x4 

8?.  9 

3  21 

4-35 

4.25 

5 

.583 

.0069 

Athlete 

21 

M 

21 

139 

63-1 

3  21 

5-00 

4  5 

4 

.458 

.0073 

22 

M 

163 

74-1 

3  21 

5.20 

5 

5 

.418 

.0056 

Adipose  tissue 

23 

M 

45 

14'  • 

63.5 

3  25 

9 

9 

.361 

-0057 

24 

M 

29 

154 

70 

3  28 

5.30 

5         '        3 

.431 

(.0062) 

Catarrhal  in'fn 

Average  .0063 


In  this  average  all  bracketed  numbers  are  omitted. 


The  results  are  also  shown  in  a  curve  (Fig.  5),  with  body  weight 
in  kilograms  as  abscissae,  and  grams  of  carbon  dioxide  excreted  per 
minute  as  ordinate.  The  curve  was  drawn  as  follows:  The  points  rep- 
resenting the  excretion  of  the  various  subjects  were  first  plotted  in 
the  usual  manner.  The  average  excretion  of  carbon  dioxide  per  minute 
per  kilogram  of  body  weight  (.0063  grams)  having  been  found,  the  to- 
tal excretion  per  minute  was  calculated  for  a  hypothetical  person  hav- 
ing a  body  weight  of  50  kilograms.  This  formed  one  point  on  the 
curve  of  average  excretion.  The  value  for  subject  14  which  coincided 
with  the  average,  formed  a  second  point.  These  points  were  now  con- 
nected by  a  straight  line  giving,  of  course,  the  curve  of  average  excre- 
tion for  a  subject  of  any  weight. 

This  average,  it  will  be  observed,  is  approximately  the  mean  of 
the  lowest  result  obtained  by  Johanssen  .0048  grams  (see  table  III) 
and  the  highest  result  by  Tigerstedt  and  Sonden  .00792  grams.  It  is 
about  5%  higher  than  the  average  of  the  results  of  Johanssen  and  Mag- 
nus-Levy (experiments  4,  5,  and  3,  table  III).  This  result  was  ob- 
tained on  a  class  of  persons  who  were  for  the  greater  part  exceptionally 
vigorous.  Furthermore,  with  few  exceptions,  the  subjects  were  acting 
for  the  first  time  as  subject  in  a  respiration  experiment.  Had  the  ex- 
periment been  repeated  several  tims  with  each  subject,  the  average  re- 
sults would  perhaps  have  been  somwhat  lower  than  that  given  in  table 
III. 

3.     Results:  It  will  be  noted  that  the  rates  of  excretion  of  carbon  di- 

—22— 


oxide  of  subject  number  8,  a  woman  having  a  body  weight  of  40  kilograms, 
and  of  number  15,  a  man  weighing  86.4  kilograms,  was  nearly  the  saino, 
the  value  for  each  closely  approximating  the  average;  also  that  the  sub- 
jects whose  values  vary  widely  from  the  average,  belonged,  for  the 
greater  part,  to  one  of  these  two  classes,  a.  Those  whose  values  are 
represented  on  the  chart  by  Ad.  The  low  results  in  these  cases  (2,  10, 
22)  was  probably  due  to  the  large  amount  of  adipose  tissue  present  in 
the  body,  since  the  metabolism  in  this  form  of  tissue  is  very  weak.  b. 
Those  whose  values  are  represented  by  N  on  the  chart.  Those  indicated 
in  this  manner  were  troubled  with  indigestion,  number  13  having  had 
severe  nausea,  and  number  20  slight  nausea  at  the  time  of  the  experi- 
ment. 

4.     Conclusions. 

1.  In  a  series  of  experiments  such  as  that  described  in  this  sec- 
tion, the  results  are  modified  somewhat,  in  individual  cases,  by  the  state 
of  health  of  the  subject.     Colds  and  indigestion  apparently  increase  the 
rate  of  excretion  of  carbon  dioxide  per  unit  of  body  weight. 

2.  The  amount  of  carbon  dioxide  excreted  per  kilogram  of  body 
weight  is  apparently  greatly  lowered  by  adipose  tissue  present  in  large 
amounts  in  the  body  of  the  subject. 

V.  INFLUENCES  WHICH  MODIFY  THE  RATE  OF  EXCRETION 
OF  CARBON  DIOXIDE  DURING  REST.* 

Introduction.  This  work  was  suggested  by  that  of  Lombard^ 
on  "Some  of  the  influences  which  affect  the  power  of  muscular  contrac- 
tion." In  that  research,  which  was  made  with  the  ergograph,  Lombard 
found  that,  in  general,  there  was  a  fall  of  muscular  power  during  the 
day,  this  result  being  noted  on  eighteen  out  of  a  series  of  twenty-three 
days.  However,  on  certain  days,  the  fall  in  power  due  to  fatigue  was 
slight  and  on  five  days  the  power  was  greater  at  the  last  experiment 
than  at  the  first.  These  exceptions  led  to  the  suspicion  that  barometric 
changes  had  an  influence  on  muscular  endurance.  When  later  a  com- 
parison was  made  between  Lombard's  endurance  curve  arid  the  curve 
of  barometric  height,  it  was  found  that,  while  no  constant  relationship 
existed  between  the  two  variables,  they  varied  in  the  same  sense  on 
twenty  out  of  twenty-three  days;  i.  e.,  in  general  "when  the  barometer 
rose  during  the  day,  or  fell  less  than  on  the  preceding  day,  the  muscu- 
lar endurance  either  rose,  or  fell  Jess  than  on  the  preceding  day." 

It  has  been  shown  furthermore,  that  while  a  diminution  of  baro- 
metric pressure  increases  both  the  respiration  rate  and  the  volume  of 
air  respired,  after  allowance  is  made  for  the  increase  of  volume  due  to 
the  lower  pressure  the  volume  respired  is  less  (Speck). 

Now,  the  effect  of  increasing  barometric  pressure  upon  the  power 
of  the  muscular  system  might  possibly  be  due  to  some  influence 

*  This  paper  was  accepted  for  publication  bv  the  officers  of  Section  VIII,  d.  Eighth 
International  Congress  of  Applied  Chemistry,  and  was  read  before  the  Section  at  a  stat- 
ed meeting  on  September  11, 1912;  BIOCHEMICAL  BULLETIN,  1912,  ii,  p.  153. 

—23— 


exerted  through  the  nervous  and  circulatory  systems  tending  to  in- 
crease the  readiness  of  metabolism;  if  such  were  the  case  then  a  varia- 
tion in  barometric  height  should  b^  accompanied  by  a  variation,  in  the 
same  sense,  in  the  rate  of  excretion  ot!  carbon  dioxide. 

Plan  of  the  experiments.  It  seemed. that  a  series  of  experiments 
carried  out  for  a  month  on  three  healthy  subjects  might  throw  light 
on  this  question,  and  also  give  interesting  results  as  regards  the  effect 
of  other  conditions  on  the  rate  of  caibon  dioxide  excretion.  A  series 
of  respiration  experiments  was  planned,  accordingly,  for  three  subjects, 
A.  and  B,  students  in  the  University  of  Michigan,  and  the  writer,  <?. 
A  and  B  were  24  and  22  years  of  age  respectively,  and  weighed,  with- 
out clothing,  158  and  159 %  pounds.  0  was  46  years  of  age  and  weigh- 
ed, exclusive  of  clothing,  148  pounds.  Each  subject  was  to  live  his  reg- 
ular daily  life  except  that  no  vigorous  muscular  exercise  was  to  be  en- 
gaged in  immediately  preceding  any  experiment,  and  that  nothing 
whatever  was  to  be  eaten  between  meals.  The  plan  of  work  is  indi- 
cated in  the  appended  summary,  \vhere  the  data  for  the  third  part  of 
each  experiment  are  placed  below  those  for  the  first  and  second: 


Hour 

Re- 

First 

I  Time  until 

Second 

Subject 

of 

dined 

experi 

Breakfast          next 

Reclined 

experi 

Dinner 

Ris 

merit 

experiment 

meat 

ing 

\ 

begun 

A      |     6 

6:45 

7:00     |7:40-8:00|     4      hr. 

11:45 

12:00 

12:40 

B           6 

7:05 

7:20      8:00-8:20      4      hr. 

12:05 

12:20 

1:00 

C 

6 

7:25 

7:40     |8:00-8-20|     4%  hr. 

12:25 

12:40 

1:00 

Subject 

Time  until  next     | 
experiment                 Reclined 

Third 
i     experiment 
begun 

launch 

Experi- 
menter 

A 
B 
C 

4     hrs. 
4      hrs. 
4V3  hrs. 

4:45 
5:00 
5:25 

5:00 

I      6:2° 

5:40 

5:40 
6:00 
6:00 

C 

A 
B 

The  routine  of  work  was  as  follows:  The  subjects  rose  at  6  o'clock 
reaching  the  laboratory  at  about  6:35.  A  reclined  upon  a  couch  at  6:45 
in  prepartion  for  the  first  experiment.  B  and  C  prepared  all  the  appa- 
ratus, making  the  initial  calibration  of  the  balance,  weighing  the  guard 
tubes,  reading  and  recording  the  barometric  height,  the  outdoor  and 
room  temperature,  etc.  In  order  to  enable  the  experimenter  to  judge 
the  better  as  to  the  physical  condition  of  each  subject,  mouth  tempera- 
ture and  pulse  were  also  taken  and  lecorded.  This  routine  at  the  lab- 
oratory was  followed  at  12  M.  and  5  P.  M. 


—24— 


TABLE  IV. 


Data  showing  the  excretion  of  carbon  dioxide  by  subjects  A  B.  and 
(7,  in  milligrams  p^r  minute. 


Date 

Subject  A 

Subject  B 

Subject  C 

December      7  A.  M 

12  M 

5  P.  M 

7A.M.  12  M. 

5P.M 

1  A.M.  12  M 

5  P.  M. 

23 
24 

406 

438 

422 
460 

447 

381 

489 

498 
422 

~56T 
541 

406 
419 

390 
409 

I  447 
409 

26 

442 

448 

466 

514 

429 

(743) 

422 

403 

428 

27 

422 

453 

466 

535 

434 

548 

390 

403 

390 

28 

403 

448 

(635) 

488 

507 

498 

397 

375 

419 

29 

407 

422 

381 

520 

553 

546 

382 

387 

456 

30 

438 

483 

405 

529 

495 

518 

419 

381 

374 

31 

425 

470 

444 

(647) 

489 

476 

390 

362 

438 

Jan. 

-   j 

2 

433 

487 

480 

438 

(611) 

570 

393 

422 

473 

3 

470 

436 

422 

416 

462 

508 

394 

377 

422 

4 

507 

435 

480 

537 

442 

553 



386 

448 

5 

469 

473 

442 

528 

466 

515 

410 



396 

6 

458 

466 

442 

-  — 

525 

531 

449 

403 

476 

7 

465 

442 

432 

439 

560 

466 

406 

386 

411 

9 

416 

436 

436 

410 

442 

462 

390 

380 

448 

10 

416 

459 

448 

455 

506 



383 

425 

473 

11 

456 

439 

426 

453 

422 

526 

363 

402 

337 

12 

446 





543 





388 





13 



















14 

405 

462 

445 

— 

476 

504 

398 

427 



16 

436 

496 

449 

469 

531 

440 

402 

396 

437 

17 

412 

453 



418 

460 





459 



18 

377 

407 

462 



459 

469. 

364 

442 

435 

19 

472 

487 

422 

445 

474 

409 

403 

438 

429 

20 

469 

476 

436 

402  |  455 

432 

402 

474 

419 

21 

462   436 

493 

399 

442  |  493 

406 

448 

434 

I 

| 

23 

428 

481 

429 

509 

442 

436 

396 

449 

429 

24 

422 

517 

495 

500 

459 

537 

409 

460 

429 

25 

422 

475 

402 



528 

486 

422 

468 

428 

26 

495  | 

561 







• 

422 

422 



Averages  

438 

462 

443 

472 

476 

501 

401 

414 

427 

—25— 


Results.  The  result  of  this  series  of  experiments  are  shown  in  Ta- 
ble IV  in  miligrams  of  carbon  dioxide  excretion  per  minute.  It  will  be 
noted  that  A's  average  for  the  mid-day  experiments  is  considerably 
higher  than  that  for  the  morning  and  evening  experiments.  This  is 
due  in  part,  at  last,  to  the  fact  that  this  subject  took  his  heartiest  meal 
in  the  morning.  The  excretion  of  carbon  dioxide  for  B  and  C,  on  the 
other  hand,  was  greatest  in  the  evening,  since  these  subjects  took 
their  dinner  at  1  p.  m. 

The  remarkably  high  excretion  shown  for  A  at  the  evening  experi- 
ment of  December  28  (635  mg.,  while  the  average  for  that  hour  for  Uiis 
subject  is  only  443  mg.)  is  explained  as  follows:  This  subject  went 
skating  in  the  afternoon  of  that  day  and  at  about  2:30  o'clock  had  the 
misfortune  to  break  through  the  ice,  becoming  wet  to  the  neck.  On  be- 
ing rescued,  he  walked  about  two  miles  in  his  frozen  clothing,  exposed 
meanwhile  to  a  strong  wind  at  a  temperature  of  about — 6.°  C.  On  reach- 
ing his  room  he  took  a  thorough  rubdown,  made  a  change  of  clothing, 
rested  for  one  and  one-half  hours,  and  appeared  at  the  laboratory  at 
the  usual  hour  for  the  experiments,  with  the  result  stated  above.  It 
will  be  noted  that  all  of  this  subject's  values  for  the  following  day,  es- 
pecially that  of  the  evening,  were  much  below  the  average,  indicating 
a  reaction  from  the  exposure  and  excitement  of  the  preceding  day.  The 
high  excretion  of  the  morning  of  January  4  is  supposed  to  be  due  to 
lunch  eaten  late  on  the  preceding  evening;  that  of  12  o'clock,  January 
26,  to  an  exceptionally  heavy  morning  meal;  and  the  low  result  of  the 
evening  of  January  19  to  an  especially  light  midday  meal. 

The  irregularity  of  results  obtained  from  B  are  somewhat  difficult 
to  explain.  Those  of  the  morning  of  December  27,  30  and  31,  were  due 
to  lunch  eaten  late  the  preceding  evening  and  in  the  case  of  the  two 
latter  results,  also  in  part  to  excessive  haste  to  reach  the  laboratory  in 
time  for  the  regular  experiment.  Other  high  results,  especially  those 
of  5  p.  m.,  December  26,  and  of  12  m.,  January  2,  were  undoubtedly 
due  to  indigestion. 

Passing  now  to  a  study  of  the  relation  of  carbon  dioxide  excretion 
to  barometric  changes,  Figure  6  will  be  found  to  embody,  in  the  form 
of  curves,  the  results  already  given  in  Table  IV,  with  time  as  abscissae, 
and  miligrams  of  carbon  dioxide  per  minute  as  ordinates;  it  presents 
curves  for  A,  B  and  C,  together  with  that  for  the  barometer  in  milli- 
meters of  mercury  and  of  the  outdoor  temperature  in  degrees  centi- 
grade. The  temperature  of  the  room  was  practically  constant  through- 
out the  series  of  experiments.  Three  curves  are  given  for  each  subject 
where  the  necessary  data  were  at  hand.  In  each  case  the  morning, 
midday  and  evening  curves  are  represented,  respectively,  by  solid,  long- 
dash  and  short-dash  lines. 

Analysis  of  the  Results.  Comparison  of  the  data  for  barometric 
pressure  and  carbon  dioxide  excretion.  Before  proceeding  to  a  rigor- 
ous mathematical  investigation  of  the  relationship  between  barometric 
change  and  carbon  dioxide  excretion,  it  seemed  desirable  to  make  a 

—26— 


comparison  of  these  two  variables  at  a  number  of  the  dates  on  which 
especially  marked  barometrical  fluctuations  took  place,  since  in  such 
cases  the  effect  would  be  more  pronounced  and  less  likely  to  be  masked 
by  other  varying  conditions,  such  as  amount  and  character  of  the  pre- 
ceding meal,  character  of  muscular  exercise,  etc.  To  facilitate  such  a 
comparison,  Tables  V.,  VI.,  and  VII,  were  prepared;  they  indicate  ex- 
periment number;  dates  between  which  the  comparison  is  made;  baro- 
metric height,  rise  or  fall;  subject,  carbon  dioxide  for  the  two  days  be- 
tween which  comparison  is  made;  rise  or  fall  of  excretion;  and  rela- 
tion between  barometric  change  and  carbon  dioxide  excretion,  whether 
direct  or  inverse.  Taking  first  the  morning  values,  it  was  found  that 
the  barometer  rose  between  7  a.  m.,  December  23,  and  7  a.  m.,  Decem- 
ber 24,  from  739  to  746,  or  7mm.  During  the  same  period  the  excre- 
tion of  carbon  dioxide  of  the  three  subjects  changed  as  follows:  That  of 
A  from  406  to  438  mg.  per  minute,  an  increase  of  32  mg.;  that  of  B 
from  381  to  489,  an  increase  of  108  mg.  and  that  of  C  from  406  to  419, 
an  increase  of  13  mg.  per  minute.  Thus  with  rising  barometer  there 
was  an  increase  in  the  rate  of  excretion  of  carbon  dioxide  in  the  case 
of  each  subject.  A  similar  result  is  obtained  in  four  other  morning 
experiments  (two  subjects).  In  three  morning  experiments  there  are 
two  direct  results  each.  One  experiment  shows  two  indirect  results,  i. 
e.,  there  is  a  change  in  carbon  dioxide  excretion  which  is  opposite  in 
sign  to  that  in  the  barometer. 

Summing  up  the  results  of  the  morning  experiments  we  have  the 
following:  Eleven  experiments  were  carried  out  on  A,  seven  on  B,  and 
eleven  on  C.  The  degree  of  correspondence  of  barometric  change  with 
carbon  dioxide  excretion  was: 


A,  7  cases  out  of  11,  or  63.6  per  cent. 

B,  6  cases  out  of  7,  or  85.7  per  cent. 

C,  cases  out  of  11,  or  55.5  per  cent. 


-27— 


x 


Izi 

•O  3 


, 
-8 

-l 


o  u         x\ 

&*  1 1 

z  z      < 


a  o  o 


*sr? 

!| 

CVJ     ^« 


g* 

oj| 

&2 
bti 

•55 

uf 

T3  O 

•oSf 

PQ  •: 

<  8 

(A   U 

^  SI 

IS1 

3^ 


M  *• 

•°H 

J* 

fO    v 

§s 

S|i 

II 

&!| 

3 
U 

•  1 

O 


TABLE  V— Data  obtained  at  7  a.  m. 


No 

Date 
Dec. 

Barometer 

"o 

V 

15" 

Excretion  of  carbon 
dioxide 

Relation    be- 
tween barome- 
tric change 
&  carbon  diox- 
ide excretion 

Heights,  mm 

Rise, 
mm 

Fall, 
mm 

Per 

minute 
mg. 

Rise, 
mg. 

Fall, 
mg. 

Direct 

Inverse 

1 

23-24 

739    -746 

7. 

~ 

A 
B 

406-438 
381-489 

32 

108 

— 

32 

108 

G 

406-419 

13 

— 

13 

2 

26-28 

745.1-721 

— 

24.1 

A 

442-403 

— 

39 

39 

B 

514-488 

— 

26 

26 

G 

422-397 

— 

25 

25 

3 

28-29 

721  -742.1 

21.1 

— 

A 

403-407 

4 

— 

4 

B 

488-520 

32 

— 

32 

G 

397-382 

— 

15 

— 

15 

4 

29-31 

742.5-736 

— 

6.1 

A 

407-425 

18 

— 

— 

18 

B 

— 

— 

— 

G 

382-390 

8 

— 

— 

8 

5 

Jan. 

2-4 

737.1-743.5 

6.4 

— 

A 

433-507 

74 

— 

74 

B 

438-537 

99 

— 

99 

G 

393-394 

1 

— 

1 

6 

5-7 

743.5-732.5 

— 

11. 

A 

469-465 

— 

4 

4 

B 

528-439 

— 

89 

89 

C 

410-406 

— 

4 

4 

7 

11-12 

753.9-737.1 

— 

16.8 

A 

456-446 

— 

10 

10 

B 

453-543 

90 

— 

— 

90 

G 

363-388 

25 

— 

— 

25 

8 

12-14 

737.1-751.2 

14.1 

— 

A 

446-405 

— 

41 

— 

41 

B 



— 

— 

— 

G 

388-398 

10 

— 

10 

9 

18-19 

748.1-739.3 

— 

8.9 

A 

377-472 

95 

— 

— 

95 

B 



— 

— 

— 

G 

364-403 

39 

— 

— 

39 

10 

23-24 

749  -739.8 

— 

9.2 

A 

428-422 

— 

6 

6  i 

B 

509-500 

— 

9 

9' 

G 

396-409 

13 

— 

— 

13 

11 

24-26 

739.8-758.8 

19. 

— 

A 

422-495 

73 

— 

73 

B 



— 

— 

— 

G 

409-422 

13 

— 

13 

The  direct  result  from  the  midday  experiments  were  as  follows: 

A,  3  cases  out  of  7,,  or  42.8  per  cent. 

B,  3  cases  out  of  9,  or  33.3  per  cent. 
C,  6  cases  out  of  9,  or  66.6  per  cent. 


From  the  evening  experiments  the  direct  results  were: 

A,  3  cases  our  of  6,  or  50  per  cent. 

B,  4  cases  out  of  9,  or  44.4  per  cent. 
C,  4  cases  out  of  8,  or  50  per  cent. 


TABLE  VI. 


Data  obtained  at  12  m. 


Dec. 

No.     Date 
1     23-24 

Barometer 
739.1r746.2 

Rise  Fall  Subject 
7.1             A 

Carbon 
Dioxide 
422^460 

Rise 
38 

Fall 

Direct  In 
verse 
38 

B 

498-422 

76 

76 

C 

390-409 

19 

19 

2     26-28 

742.5-726.9 

15.6    A 

446-448 

B 

429-507 

78 

78 

C 

403-375 

28 

28 

3     28-29 

726.9-742-5 

11.6             A 

448-422 

26 

26 

B 

507-553 

46 

46 

Jan 

C 

375-387 

12 

12 

4     29-31 

742.5-736.1 

6.4    A 

422-470 

48 

48 

B 

553-489 

64 

64 

C 

387-362 

25 

25 

5       2-4 

738.9-745.1' 

6.2            A 

487r435 

52 

62 

B 

(611-442) 

169 

169 

C 

422-386 

36 

36 

6       5-7 

743.5-732.9 

10.6    A 

473-442 

31 

31 

B 

466-560 

94 

94 

C 

403-386 

17 

17 

7     18-19 

747.7-740.1 

7.8    A 

407-487 

80 

80 

B 

459-474 

15 

16 

C 

442-438 

4 

4 

8     23-24 

749.8-738.8 

11.     A 
B 

480-517 
442-459 

37 
17 

37 
17 

C 

449-460 

11 

11 

9     24-26 

738.8-758.5 

19.6            A 

517r561 

44 

44 

B 

459-528 

69 

69 

C 

460-422 

38 

38 

—30— 


TABLE  VII. 


Data  obtained  at  5  p.  m. 

No.       Date          Barometer        Rise  Fall  Subject 

Dec. 

1  23-24       739.1-747.1         8  A 

B 
C 

2  26-27     741.5-718.2  12.9    A 

B 
0 

3  27-28     718.2-738.1     19.9  A 

B 
C 

4  29-31     742.5-737.5  5        A 

B 
Jan.  C 

5  2-4       740-745  5  A 

B 
C 

6  5-7       744.1-732.9  11.2    A 

3 
(3 

7  18-19     742.9-739.5  3.4    A 

B 
C 

8  23-24     747.8-740  7-8    A 

B 

/~< 

9  24-25     740.755.1        15.1  A 

B 
C 


Carbon       Rise 
Dioxide 


Fall    Direct    In- 
verse 


567-541 

26 

26 

447-409 

38 

38 

466-466 

(743-548) 

195 

195 

428-390 

38 

38 

466  635 

169 

169 

548-498 

50 

50 

390-419 

39 

39 

381-444 

63 

63 

546-476 

70 

70 

456-438 

18 

18 

480-480 

570-553 

17 

17 

473-448 

25 

25 

442-432 

10 

10 

515-466 

49 

49 

396-411 

15 

462-422 

40 

40 

469-409 

60 

60 

435-429 

6 

6 

429-495 

66 

66 

436-537 

101 

101 

429-429 

495-402 

93 

93 

537-486 

51 

51 

429-428 

1 

1 

Or,  out  of  a  total  of  seventy-seven  experiments,  there  was  direct  rela- 
tionship between  barometric  change  and  and  carbon  dioxide  excretion 
in  forty-two  experiments,  or  54.5  per  cent. 

It  will  be  seen  from  these  results  that  the  apparent  degree  of  corre- 
spondence, so  far  as  it  is  revealed  by  this  method  of  analysis,  is  greater 
in  the  morning  experiments  than  in  those  carried  out  at  midday  or  in 
the  evening.  This  is  probably  due  to  the  fact  that  in  the  morning  not 
merely  the  digestive  organs,  but  the  whole  system,  is  in  a  more  uniform 
condition  than  at  any  other  time  during  the  twenty-four  hours. 

Application  of  the  method  of  least  squares.  It  now  seemed  desira- 
ble to  subject  the  results  obtained  in  this  series  of  experiments  t3  a 
more  rigorous  analysis  than  that  just  described,  with  a  view  of  discov- 
ering what  is  the  degree  of  correlation  between  the  two  variables,  the 


—31— 


barometric  height  and  the  rate  of  excretion  of  carbon  dioxide,  during 
muscular  rest.  The  data  obtained  in  the  experiments  were,  therefore, 
examined  by  the  method  of  least  squares,  which  was  applied  separately 
to  the  three  sets  of  data  from  each  subject  in  order  that  the  effect  of 
different  times  of  day  might  be  determined  separately. 

In  Table  VIII  are  given  the  barometric  height  and  the  correspond- 
ing carbon  dioxide  excretionf;  the  problem  is  to  find  the  correlation  be- 
tween these  two  quantities,  and  also  the  regression  of  carbon  dioxide  on 
barometric  height,i.  e.,  the  amount  of  change  in  excretion  of  carbon  di- 
oxide for  a  milimeter  change  in  barometric  height.  The  means  of  col- 
umns 1  and  2  are  obtained  in  the  usual  manner,  by  dividing  the  total 
in  each  column  by  the  number  of  experiments  (N).  Having  obtained 
these  means,  two  additional  columns  are  formed,  giving  the  deviation 
of  each  observation  from  the  mean  of  its  column.  In  columns  5  and  6 
are  entered  the  squares  of  the  deviations  (X2  andY2).  The  standard 
deviation  OJ  is  now  obtained  by  dividing  the  sum  of  the  squares  in 
the  fifth  column  by  the  number  of  experiments,  2V,  and  extracting  the 
square  root  of  the  quotient;  the  standard  deviation  for  y  is,  of  coursa 
found  in  the  same  manner. 


/ 1769.71  /ZY3      II 

-V-:-=7-8and*>V— V- 


24951 

-=29.3 
29  '  IV  29 


*  The  data  are  those  obtained  from  morning  experiments  on  subject  A. 


—32— 


Relation  of  Carbon  Dioxide  Excretion  to 
TABLE  VIII— 7  A. 


Barometric  Change. 
M. 


Products  (x  y) 

Barometer 
Millimetres 

Carbon 
Dioxide 

X 

y 

o 
X 

O 

y 

Negative 

Positive 

739 

Milligrams 
406 

—4 

—32 

16 

1024 

128 

746 

438 

3 

0 

9 

— 

745.1 

442 

2.1 

4 

4.41 

16 

8.4 

726.2 

422 

—16.8 

—16 

282.24 

256 

268.8 

721 

403 

—22 

—35 

484 

1225 

770 

742.1 

407 

-0.9 

—31 

.81 

961 

27.9 

740 

438 

—3 

0 

9 

736 

425 

—7 

—13 

49 

169 

91 

737.1 

433 

—5.9 

—5 

34.81 

25 

29.5 

741.3 

470 

—1.7 

32 

2.89 

1024 

54.4 

743.5 

507 

.5 

69 

.25 

4761 

34.5 

743.5 

469 

.5 

31 

.25 

961 

15.5 

742.3 

458 

—  .7 

20 

.49 

400 

14 

732.5 

465 

—10.5 

27 

110.25 

729 

283.5 

751.5 

416 

8.5 

—22 

72.25 

484 

187 

751  .  4 

416 

8.4 

—22 

70.86 

484 

184.8 

753.9 

456 

10.9 

18 

118.81 

324 

196.2 

736.1 

446 

—5.9 

8 

34.81 

64 

47.2 

751.2 

405 

8.2 

—33 

67.24 

1089 

270.6 

746.5 

436 

3.5 

—2 

12.25 

4 

7 

747.8 

412 

4.8 

—26 

23.04 

676 

124.8 

748.2 

377 

5.2 

—61 

27.04 

3721 

317.2 

739.3 

472 

—3.7 

34 

13.69 

1156 

125.8 

745.5 

469 

—2.5 

31 

6.26 

961 

77.6 

743.7 

462 

.7 

23 

.49 

576 

16.8 

749. 

428 

6. 

—10 

36 

100 

60 

739.8 

422 

—3.2 

—16 

10.24 

256 

51.2 

747.9 

422 

4.9 

—16 

24.01 

256 

78.4 

758.8 

495 

15.8 

57 

249.64 

32-49 

900.6 

1769.71 

24951 

1754.7 

2622.7 

1754.7 

868 


-—7.8 


•Coefficient  of  correlation— 


/J4951  _ 
r2=r  \'29~~ 


Zxy   __          868 
Nfft  <r2  ~~  29XT.8 X 2 9 .3 


12(T2 

Regression— —.45 

0"a 

—33— 


The  products  XY  are  now  collected,  the  negative  in  column  7  and 
the  positive  in  column  8,  and  the  totals  determined.    We  have,  then, 
—  1754.7=+868. 


Prom  this  coefficient  of  correlation  (r)  is  obtained: 


868 

=+.12 


29X.7.8X29.3 


The  positive  sign  of  this  coefficient  indicates,  of  course,  that  the  rela- 
tionship between  barometric  change  and  carbon  dioxide  excretion  in 
this  case  is  direct  or  that  the  two  variables  change  in  the  same  sense. 
Since  a  coefficient  of  correlation  of  1  indicates  perfect  correlation,  the 
result  obtained  in  the  series  of  experiments  represented  in  Table  IV 
indicates  a  slight  degree  of  correlation.  The  probable  error  of  a  cor- 
relation coefficient  of  this  value  for  a  series  of  25  observations  is  at 
least  0.13  so  that  the  value  of  r  is  0.12±0.13. 


Relation  of  carbon  dioxide  excretion  to  barometric  change. 
TABLE  IX— A.— 12  m. 


Barometer 

Carbon 
dioxide 

Products  (XY) 

reading,  mm 

excretion,  mg. 

X 

Y 

X2 

Y2 

Negative 

Positive 

739.1 

422 

—  4.2 

r-40 

17.64|  1,600 

-   |       168 

746.2 

460 

2.9 

-  2 

8.41 

4 

5.8 



742.5 

448 

—  0.8 

—14 

0.64 

196 

^— 

11.2 

722.1 

453 

—21.2 

c 

449.44 

81 



i'jU.8 

726.9 

448 

—16.4 

—14 

268.96 

196 

229.6 

742.5 

422 

—  0.8 

—40 

0.64 

1,600 



32 

740.1 

483 

—  3.2 

21 

10.24 

441 

67.2 



736.1 

470 

—  7.2 

8 

51.84 

64 

57.6 



738.9 

487 

-  4.4 

25 

19.36 

625 

110. 



742.9 

436 

-  0.4 

—26 

0.16 

676 



10.4 

74F»   1 

4qr 

1    8 

27 

9     04 

700 

48    fi 

1  ^O  .  JL 

743.5 

^00 

473 

I  •  O 

0.2 

&  i 

11 

O  •  &T. 

0.04 

I  £tv 

121 

TiO  •  D 

2.2 

739.9 

466 

-  3.4 

4 

11.56 

16 

13.6 

,  

7QO   Q 

442 

-in   4 

20 

108   Ifi 

400 

908 

1  -  >_   .   .' 

745.8 

TTLJ 

436 

J.V  •  TC 

2.5 

AfU 

—26 

J.VO  .  .LO 

6.25 

TtU  V 

676 

65 

£UO 

753.2 

459 

9.9 

o 

98.01 

9 

29.7 



749.3 

439 

6.6 

—23 

36.00 

529 

151.8 



753.6 

462 

10.3 

0 

106.09 

0 





747.5 

496 

4.2 

34 

17.64|   1,156 



142.8 

748.1 

453 

4.8 

-  9 

23.04         81 

43.2 



747.9 

407 

4.6 

—55 

21.16 

3,025 

253.0 



740.1 

487 

—  3.2 

25 

10.24 

625 

80. 



741.1 

476 

0.8 

14 

0.64 

196 



11.2 

743.9 

436 

0.6 

—26 

0.36 

676 

15.6 



749.8 

481 

6.5 

19 

42.25 

3611 



123.5 

738.8 

517 

-  4.5 

55 

20.25 

3,025 

247.5 



752.9 

475 

9.6 

13 

92.16 

169 



124.8 

758.4 

561 

15.1 

99 

228.  01|  9,801 

—  1 

1,494.9 

1 

11,642.43127,0781  1,174.61  2,749.4 

1,174.4 

1,574.6 


27,078 


Coefficient  of  correlation: 


— 1,574.6 

2(>7/)  1,574.6 


28X7.65X31.1 


=+0,230 


0.23652 
Regression  =  -  -  -  =0.95 


—35— 


Relation  of  Carbon  Dioxide  Excretion  to  Barometric  Change. 
TABLE  X— A,  5  P.  M. 


Barometer 
Millimetres 

Carbon 
Dioxide 
Milligrams 

X 

* 

X2 

Y2 

Products  (xy) 

Negative 

Positive 

741.1 

741.1 

447 

466 

4.1 
—1.9 

4 
23 

16  .  81 
3.61 

16 

529 

43.7 

16.4 

718.2 

466 

—24.8 

23 

615.04 

529 

570.4 

742.5 

381 

.5 

—62 

.25 

3844 

31 

739 

405 

—  4 

—38 

16 

1444 

152 

737.5 

444 

—5.5 

1 

30.25 

1 

5.5 

740 

480 

—3 

37 

9 

1369 

111 

744.1 

422 

1.1 

—21 

1.21 

441 

23.1 

745 

480 

2 

37 

4 

1369 

74 

744.1 

442 

1.1 

—1 

1.21 

1 

1.1 

739.1 

442 

—3.9 

-j 

15.21 

1 

3.9 

732.9 

432 

—10.1 

—11 

102.01 

121 

111.1 

746 

436 

3 

—7 

9 

49 

21 

756.2 

448 

13.2 

5 

174.24 

25 

66 

744.1 

426 

1.1 

—17 

1.21 

289- 

18.7 

753.8 

445 

10.8 

2 

116.64 

4 

21.6 

711.1 

449 

4.1 

6 

16.81 

36 

24.6 

742.9 

462 

i 

19 

..01 

361 

1.9 

739.5 

422 

—3.5 

—19 

12.25 

361 

66.5 

743.9 

436 

.9 

—7 

.81 

49 

6.3 

744.3 

493 

1.3 

50 

1.69 

2500 

65 

747.8 

429 

4.8 

—14 

23.04 

196 

67.2 

740 

495 

—3 

52 

9 

2604 

156 

755.1 

402 

12.1 

—41 

146.41 

1681 

496.1 

1315.71       17620       1522. 
632.1 

—889.9 


'1315.71 
*'=     ^  '—sa =7.4 


632.1 


24 


=27.1 


=—  889,9. 


Coefficient  of  Correlation^ 


889.9 


1^3=24X7.4X27.1=  —.16 


— 16Xcr2 

Regression  = ='  — .58 

<ra 


Relation  of  Carbon  Dioxide  Excretion  to  Barometric  Change. 
TABLE  XI— B,  7  A.  M. 


Barometer 
Millimetres 

Carbon 
Dioxide 
Milligrams 

X    i 

Y 

X 

Y2 

Products  (xy  ) 
Negative        Positive 

739 

381 

—2.6 

—97 

6.76 

9409 

252.2 

746 

489 

4.4 

11 

19.36 

121 

48.4 

745.1 

514 

3.5 

36 

12.25 

1296 

126 

726.2 

535 

—  15.4 

57 

237.16 

3249 

877.8 

721 

488 

—20.6 

10 

424.36 

100 

260 

742.1 

520 

.5 

42 

.25 

1764 

21 

740 

529 

—1.6 

51 

2.56 

2601 

81.6 

737.1 

438 

—4.5 

—40 

20.25 

1600 

180 

741.3 

416 

-   .3 

—62 

.09 

2844 

18.6 

743.5 

537 

1.9 

59 

3.61 

3481 

112.1 

743.5 

528 

1.9 

50 

3.61 

2500 

95 

732.5 

439 

—9.1 

—39 

82.81 

1521 

354.9 

751.5 

410 

9.9 

—68 

98.01 

4624 

673.2 

751.4 

455 

9.8 

oq 
^o 

96.04 

529 

225.4 

753.9 

453 

12.3 

—25 

151.29 

625 

307.5 

737.1 

543 

—4.5 

65 

20.25 

4225 

292.5 

746.5 

469 

—4.9 

n 

24.01 

81 

44.1 

747.8 

418 

6.2 

—60 

38.44 

3600 

37.2 

739.3 

445 

—2.3 

—33 

5.29 

1089 

75.9 

745.5 

402 

3.9 

—76 

15.21 

5775 

295.4 

743.7 

399 

2.1 

—79 

4.41 

6241 

165.9 

749 

509 

7.4 

31 

54.76 

961 

229.4 

739.8 

500 

—1.8 

22 

3.24 

484 

39.6 

1324.02   59721   3301.2 
1513.5 


1787.7 


f 

'-  v 


59721 


24 


=49.8 


2    (xy)=— 1787.7 


Coefficient  of  Correlation— 


1787.7 


24X7.4X49.8 


=—.2 


—  .2(T2 

Regression^  -  -•=  —  .13 


1513.5 


—37— 


Relation  of  Carbon  Dioxide  Excretion  to  Barometric  Change. 
TABLE  XII— B,  12  M. 


Carbon 
Barometer        Dioxide 
Millimetres  Milligrams           x 

739.1              498          ^3.6 

y 

"l7 

X 

12. 

2 
96 

2 

289 

Products  txy) 
Negative        Positive 

61.2 

746 

.2 

422 

—3 

.5 

—59 

12. 

25 

3481 

206 

.5 

742 

.5 

429 

.2 

—52 

04 

2704 

10 

.4 

722 

.1 

434 

—20 

.6 

—48 

424. 

36 

2304 

988.8 

726 

.9 

507 

—15 

.8 

26 

249. 

64 

676 

410 

.8 

742 

.5 

553 

— 

.2 

72 

. 

04 

5184 

14 

.4 

740 

.1 

495 

—  2 

.6 

14 

6. 

76 

196 

36 

.4 

736 

.1 

489 

—  6 

.6 

8 

43. 

56 

64 

52 

.8 

742 

.9 

462 

.2 

19 

04 

361 

3 

.8 

745 

.1 

442 

2 

.4 

39 

5. 

76 

1521 

93 

.6 

743 

.5 

466 

.8 

—15 

64 

225 

12 

739 

.9 

525 

—  2 

.8 

44 

7. 

84 

1936 

123 

.2 

732 

.9 

560 

—  2 

.8 

79 

7. 

84 

6241 

221 

.2 

745 

.8 

442 

3 

.1 

—39 

9. 

61 

1521 

120 

.9 

753.2 

506 

10 

.5 

25 

110. 

25 

625 

262.5 

749 

.3 

422 

6 

.6 

—59 

43. 

56 

3481 

389 

.4 

753 

.6 

476 

10 

.9 

—5 

118. 

81 

25 

54 

.5 

747 

.5 

531 

4 

.8 

50 

23. 

04 

2500 

240 

748 

.1 

460 

5 

.4 

—21 

29. 

16 

441 

113 

.4 

747 

.9 

459 

5 

.2 

—22 

27. 

04 

484 

114 

.4 

740 

.1 

474 

—  2 

.6 

^-1 

6. 

76 

49 

18.2 

744 

.1 

455 

1 

.4 

—26 

1. 

96 

676 

36 

.4 

743 

.9 

442 

1 

.2 

—39 

1. 

44 

1521 

46 

.8 

749 

.8 

442 

7 

.1 

—39 

50. 

41 

1521 

276 

.9 

738 

.8 

459 

—  3 

.9 

—22 

15. 

21 

484 

85.  8 

752 

.9 

528 

10 

.2 

47 

104. 

4 

2209 

479.1 

1313.02   40719   2399     2074.7 

2074.7 

—324.3 


26 


=—  324.3 


Coefficient  of  Correlation^  ___    _  =: 


26X7.1X39.5 


— .04cr2 

Regression^ = — .09 

0*1 


—38— 


Relation  of  Carbon  Dioxide  Excretion  to  Barometric  Change. 
TABLE  XIII— B,  5  P.  M. 


Barometer 
Millimetres 

731.1 

Carbon 
Dioxide 
Milligrams           x 

567          —2.9 

y 
66 

8 

x'2             y2 
.41        4356 

Products  [xy] 
Negative       Positive 

191.4 

747.1 

541 

5.1 

40 

26 

.01         1600 

204 

718.2 

548 

—23.8 

47 

566 

.44         2209 

1118.6 

738.1 

498 

—3.9 

o 

15 

.21              9 

11.7 

742.5 

546 

.5 

45 

.25         2025 

22.5 

739 

518 

—  3 

17 

9 

289 

51 

737.5 

476 

—4.5 

—25 

20 

.25           625 

112.5 

740 

570 

a 

69 

4 

4761 

138 

744.1 

508 

2.1' 

7 

4 

.41            49 

14.7 

745 

553 

3 

52 

9 

2704 

156 

744.1 

515 

2.1 

14 

4 

.41          196 

29.4 

739.1 

531 

—2.9 

30 

8 

.41           900 

87 

732.9 

466 

—9.1 

—35 

82 

.81         1225 

318.5 

746 

462 

4 

—39 

16 

1521 

156 

744.1 

526 

2.1 

25 

4 

.41           625 

52.  S 

753.3 

504 

11.3 

3 

127 

.69               9 

33.9 

747.1 

440 

5.1 

—61 

26 

.01         3721 

311.1 

742.9 

469 

.9 

—32 

.81         1024 

28.8 

739.5 

409 

—2.5 

—92 

6 

.25         8464 

230 

743.9 

432 

1.9 

—69 

3 

.61         4761 

131.1 

744.3 

493 

2.3 

—  8 

5 

.29             64 

18.4 

747.8 

436 

5.8 

—65 

33 

.64         4225 

377 

740 

537 

—2 

36 

4 

1296 

72 

7.55 

486 

13.1 

—15 

171 

.61           225 

196.5 

1157 

.93       46883 

2876.9 

1185.  V 

1185.7 

1691.2 

ff_      /1157.93 

.9 

/468S3 

—  44  2 

\     24 

ffr~^    24 

2  (ay)  =  —1691.2 

Coefficient 

of  Correlation— 

2(«» 

/    t 

1691.2 

72     =-23 

\ 

Nov 

'* 

24X6.9X44 

E 

legressic 

— 

.23<r, 

-.17 

>n  —  — 

*i 

Relation  of  Carbon  Dioxide  Excretion  to  Barometric  Change. 
TABLE  XIV— C,  7  A.  M. 


Barometer 
Millimetres 

739 

Carbon 
Dioxide 
Milligrams           x 

406          —3.8 

y 
5 

X2 

14,44 

Products  [xy] 
y           Negative      Positive 

25           19 

746 

419 

3.2 

18 

10.24 

324 

57.6 

745.1 

422 

2.3 

21 

5.29 

441 

48.3 

726.2 

390 

—16.6 

—11 

275.56 

121 

182.6 

721 

397 

—21.8 

—  4 

475.24 

16 

87.2 

742.1 

382 

—     .5 

—19 

.25 

361 

9.5 

740 

419 

—  2.8 

18 

7.84 

324          50.4 

736 

390 

—  6.8 

—11 

46.24 

121 

74.8 

737.1 

393 

—5   .7 

—  8 

32.49 

64 

45.6 

741.3 

394 

—1   .5 

—  7 

2.25 

49 

10.5 

743.5 

410 

.7 

9 

49 

81 

6.3 

742.3 

449 

—     .5 

48 

.25 

2304           24 

732.5 

406 

—10.3 

5 

106.09 

25           51.5 

751.5 

390 

8.7 

11 

75.69 

121 

95.7 

751.4 

383 

8.6 

18 

73.96 

324 

154.5 

753.9 

363 

11.1 

38 

123.21 

1444 

421.8 

737.1 

388 

—5   .7 

13 

32.49 

169           74.1 

751.2 

398 

8.4 

—  3 

70.56 

9           25.2 

746.5 

402 

3.7 

1 

13.69 

1 

3.7 

748.2 

364 

5.4 

—37 

29.16 

1369         199.8 

739.3 

403 

—3   .5 

2 

12.25 

4             7 

745.5 

402 

2.7 

1 

7.29 

1 

2.7 

743.7 

406 

.9 

5 

.81 

25 

4.5 

749 

396 

6.2 

—  5 

38.44 

25           31 

739.8 

409 

—  3 

8 

9 

64           24 

747.9 

422 

5.1 

21 

26.01 

441 

107.1 

758.8 

423 

16 

21 

256 

441 

336 

1745.23 

8693         506 

1734.2 

506 

1228.2 

<•=, 

11745. 

23      =8 

/                   =17  9 

V      27 

199S  9 

V     27 

Coffiecient  of 

Correlations2!^*       = 

1228.2 

—   31 

6 

27X8X17.9 

.316<r2 

Regression^ =.7 

<*•> 

—40-- 


Relation  of  Carbon  Dioxide  Excretion  to  Barometric  Change. 

TABLE  XV—  C,  12 

M. 

Barometer 
Millimetres 

749.1 

Carbon 
Dioxide 
Milligrams           x 

390           -  4.2 

y 
—24 

X2 

17.64 

576 

Products  [xy] 
Negative    Positive 

100.8 

746.2 

409 

2.9 

-  5 

8.41 

25 

14.5 

742.5 

403 

-  '.8 

i—ll 

.64 

121 

8.3 

722.1 

403 

—21.2 

—11 

449.44 

121 

233.2 

726.9 

375 

—16.4 

—39 

268.96 

1521 

639.6 

742.5 

387 

—     .8 

—27 

.64 

729 

21.6 

740.1 

381 

-  3.8 

i—33 

10.24 

1089 

105.6 

736.1 

362 

-  7.2 

—52 

51:84 

2704 

374.4 

738.9 

422 

-  4.4 

8 

19.36 

64 

35.2 

742.9 

377 

.4 

—37 

.16 

1369 

14.8 

745.1 

386 

1.8 

—28 

3.24 

784 

50.4 

739.9 

403 

-  3.4 

—11 

11.56 

121 

37.4 

732.9 

386 

—10.4 

—28 

108.16 

•    784 

291.2 

745.8 

380 

2.5 

—34 

6.25 

1156 

85 

753.3 

425 

9.9 

11 

98.01 

121 

108.9 

749.3 

402 

6 

—12 

36 

144 

72 

753.6 

427 

10.2 

13 

106.09 

169 

133.9 

747.5 

396 

4.2 

—18 

17.64 

324 

75.6 

748.1 

459 

4.8 

45 

23.04 

2025 

216 

747.9 

442 

4.6 

28 

21.16 

784 

128.  S 

740.1 

438 

-  3.2 

26 

10.24 

676 

83.2 

744.1 

474 

.8 

60 

.64 

3600 

48 

743.9 

448 

.6 

34 

.36 

1156 

20.4 

749.8 

449 

6.5 

35 

42.25 

1225 

227.5 

738.8 

460 

-  4.5 

46 

20.25 

2116 

207 

752.9 

468 

9.6 

54 

92.16 

2916 

518.4 

758.4 

422 

15.1 

8 

228.01 

64 
26484 

120.8 

1652.08 

622.9         3350.5 

622.9 

2627.6 

11652.08      _ 
ffl~     \        27~                                   ~i 

J  26484 
27 

=31.3 

Coefficient  of  Correlations 


2627.6 

_____  s  .39 


27X7.8X31.3 


.39cr2 
Regression^  --  =  1.5 


—41— 


Relation  of  Carbon  Dioxide  Excretion  to  Barometric  Change. 
TABLE  XVI— C,  5  P.  M. 


Carbon 
Barometer        Dioxide               x 
Millimetres  Milligrams 

739.1              447         —  2. 

9 

y 
20 

x'2 
8.41 

y2 
400 

Products  [xy] 
Negative    Positive 

58 

747, 

.1 

409 

5, 

,1 

—18 

26 

.01 

•  324 

91.8 

741.1 

428 

t—     , 

,9 

1 

.81 

1 

.9 

718. 

,2 

390 

—23. 

8 

—37 

566 

.44 

1369 

880. 

5 

738. 

1 

419 

—  3. 

9 

—8 

15 

.21 

64 

31.2 

742. 

5 

456 

5 

29 

.25 

841 

14. 

5 

739 

374 

-  3 

—53 

9 

2809 

159 

737. 

5 

438 

-  4. 

5 

11 

20 

.25 

121 

49.5 

740 

473 

—  2 

46 

4 

2116 

92 

744. 

1 

422 

'    2. 

1 

—  5 

4 

.41 

25 

10.5 

745 

448 

3 

21 

9 

441 

63 

744. 

1 

396 

2. 

1 

—31 

4 

.41 

961 

65.1 

739. 

1 

476 

—  2. 

9 

49 

8 

.41 

2401 

142.1 

732. 

9 

411 

-  9. 

1 

—16 

82 

.81 

256 

145. 

6 

746 

448 

4 

21 

16 

441 

84 

756. 

2 

473 

14. 

2 

46 

201 

.64 

2116 

653. 

2 

744. 

1 

337 

2. 

1 

—90 

4 

.41 

8100 

180.9 

747. 

1 

437 

5. 

1 

10 

26 

.1 

100 

51 

742. 

9 

435 

9 

8 

.81 

64 

7. 

2 

739. 

5 

429 

—  2. 

5 

2 

6 

.25 

4 

5 

743. 

9 

419 

1. 

9 

—8 

3 

.61 

64 

35.2 

744. 

3 

434 

2. 

3 

7 

5 

.29 

49 

16. 

1 

747. 

9 

429 

5. 

8 

2 

33 

.64 

4 

11. 

6 

740 

429 

—  2 

2 

4 

4 

4 

755. 

1 

428 
4 

13. 

1 

1 

171 

.61 

1 

23076 

13. 

1 

1232.69 

805. 

2130. 

i 

805 

r-V 


1325.1 


_=  7.02 
25 


123076 


=30.38 


2  (xy)  =1325.1 


Coefficient  of  Correlation=        x   "     =;•    _  _  =+.248 

N<rV*  25X7.02X30.38 

.  248<ra 
Regression= —    — =1.07 


[2— 


The  results  of  the  whole  series  of  experiments  are  summed  up  in 
Table  XVII. 

TABLE  XVII. 


General  Summary. 


Sub- 

1 

1 

ject 

Hour 

X2 

y'2 

W 

<?i 

<T2 

„  ,       .     Coeffic'nt 
S(xy)     ofeorre- 

Probable 
error 

Regres- 
sion 

1 

I 

lation,  r 

A 

7  A.M. 

1,754.7 

24,951 

29 

Y.8  |29.3 

868.     +0.12 

±0.13 

0.45 

A 

12  M. 

1,642.4 

27,078 

28 

7.65 

31.1 

1,574.6  +0.236 

±0.126 

0.95 

A 

5  P.M. 

1,315.71 

17,620 

24 

7.4 

27.1 

589.9 

—0.12   |±0.126 

—0.44 

B 

7  A.M. 

1,324.02 

59,721 

24 

7.4 

49.8 

1,787.7 

—0.2 

±0.129 

!—  0.13 

B 

12  M. 

1,313.02 

40,919 

26 

6.9 

44.2 

818.3 

—0.04 

±0.124|—  0.09 

B 

5  P.M. 

1,158.7 

46,883 

25 

6.5    64.0 

1,926.1 

—0.23 

±0.13 

—0.17 

C 

7  AJ.M. 

1,228.2 

8,693 

27 

8.0 

17.9 

1,228.2 

+0,316|±Q.12 

0.7 

C 

12  M. 

1,652.0 

26,484 

27 

7.8  131.2 

2,627.  6,+0.  39 

±0.11 

1.5 

C 

5  P.M. 

1,232.6 

23,076 

25  7.  02)30.38 

1,325.  1|+0.  248 

±0.125 

1.07 

Conclusions : 

There  were  indications  in  this  work  of  an  influence  of  barometric 
change  on  carbon  dioxide  excretion  in  the  case  of  one  subject,  C,  since 
there  were  three  positive  coefficients  of  correlation  having  the  value  of 
C.316,  0.39,  and  0.248,  for  morning,  noon  and  evening  experiments  (per- 
fect correlation  would  be  indicated  by  a  coefficient  of  1) ;  a  slight  direct 
influence  is  also  indicated  in  the  case  of  A,  whose  coefficients  were  0.12, 
0.236  and  — 0.12.  In  the  case  of  B,  whose  values  of  carbon  dioxide  ex- 
cretion throughout  the  work  were  quite  irregular,  (See  Table  XVIII) 
there  were  three  negative  coefficients  with  values  of  — 0.2,  — .04  and 
— .23,  respectively. 


—43— 


TABLE  XVIII. 


Carbon  Dioxide 

Excretion  in 
Milligrams  per 
Minute 


A.  M. 


ABC 
Cases  Cases  Cases 


M        P.  M.        A.  M.        M.       P.  M.     A   M. 


P.  M. 


361  —  370  

• 

I    2 

1 

371  —  380 

I 

I 

1 

1 

3 

1 

381  —  390  .  . 

i 

1 

5 

5 

1 

391  —  400  

1 

1 

6 

1 

1 

401—410  
411  —  420  

4 
3 

1 

2 

2 

2 

1 

8 
2 

5 
1 

1 
3 

421'  —  430  

5 

2 

4 

3 

3 

3 

5 

431  —  440  

4 

5 

3 

2 

1 

3 

1 

4 

441  —  450   

2 

3 

17 

1 

4 

1 

3 

3 

451  —  46Q 

2 

4 

1 

2 

4 

1 

1 

461  —  470  

5 

4 

2 

1 

2 

3 

2 

471  —  480  

1 

3 

2 

1 

1 

3 

481  —  480 

3 

2 

1 

1 

491  —  500  

1 

1 

2 

2 

2 

501  —  510  

1 

2 

2 

2 

* 

£11  —  520 

1 

2 

2 

521  —  530 

2 

2 

1 

531  —  540  

2 

1 

21 

547  —  550 

1 

1 

3 

551  —  560  

1 

1 

1 
1 

561  —  570  

1 

i 

1 

These  results  are,  perhaps,  what  might  have  been  expected.  The 
barometric  change  is  evidently  a  minor  influence  and  its  effect  is 
therefore  liable  to  be  masked  by  other  influences,  such  as  exercise, 
amount  and  character  of  meals,  etc.  Moreover,  the  effect  of  varying 
barometric  pressure  upon  the  muscular  endurance  noted  by  Prof.  Lom- 
bard in  his  own  case  has  not  been  verified  in  the  case  of  other  sub- 
jects. The  writer  is  of  the  opinion  that  if  a  series  of  parallel  ergo- 
graphic  and  respiration  experiments  were  made  on  a  number  of  sub- 
jects, it  would  be  found,  in  general,  that  positive  effects  of  barometric 
changes  on  muscular  endurance  are  accompanied  by  positive  cofficients 
of  correlation  of  barometric  change  with  rate  of  excretion  of  carbon 
dioxide. 


—44— 


VI.     THE  EXCRETION  OF  CARBON  DIOXIDE  DURING  UNI- 
FORM MUSCULAR  WORK,  AND  ITS  RELATION  TO  THE 
SECONDARY  RISE  OF  THE  PULSE  RATE, 

1.     Method. 

About  twenty  experiments  were  made  to  find  the  general  cours? 
of  the  changes  in  rate  of  excretion  of  carbon  dioxide  resulting  from 
work.  The  work  was  done  on  the  bicycle  with  stationary  frame.  This 
is  driven  by  the  subject  at  a  uniform  rate  which  is  continuously  record- 
ed. The  graphic  record  of  carbon  dioxide  excretion  is  taken  on  a  slowly 
revolving  drum  along  with  records  of  respiratory  movements,  revolu- 
tions of  the  bicycle  crank  shaft,  and  time  in  seconds.  On  a  loop  of  pa- 
per passing  around  two  drums  and  moving  more  rapidly,  the  pulso 
is  recorded  along  with  a  time  curve,  giving  seconds. 

By  means  of  a  Morse  key  and  an  electric  signal  on  each  drum,  the 
corresponding  parts  of  the  two  records  are  indicated. 

In  beginning  an  experiment,  the  subject  puts  on  the  mask,  mounts 
the  wheel,  the  pneumograph  and  pulse  tambour  are  adjusted  and  test- 
ed, and  then  the  mask  is  connected  to  the  tubes  leading  to  the  apparat- 
us for  determining  carbon  dioxide.  The  drums  are  started,  and  the 
subject  sits  quietly  on  the  bicycle  until  sufficient  length  of  record  has 
been  made  to  show  the  normal  rate  of  pulse,  breathing,  and  excretion 
of  carbon  dioxide.  Then,  at  a  signal  from  the  experimenter  ho  begins 
to  drive  the  wheel  in  unison  with  a  metronome  placed  before  him,  and 
the  records  continue.  The  balance  is  handled  as  described  in  the  pre- 
ceding section.  The  electric  signal  connected  with  the  bicycle  indi- 
cates the  moment  of  starting  and  stopping,  and  the  speed  of  revolution. 
On  cessation  of  the  work  the  records  continue  until  the  rate  of  excre- 
tion has  returned  approximately  to  what  it  was  before  the  work  began, 
as  indicated  by  the  slant  of  the  line  described  by  the  recording  lever. 
The  experiment  then  ends.  A  record  taken  in  this  way  is  shown  in 
Pig.  7. 


Figure? -Graphic  iccord  of  carbon  dioxide  excretion  during  bicycling.  To  be  read  from 
left  to  right.  K,  respiratory  movements.  CO2 record  made  by  chemograph.  The  descending 
lines,  as  AC, are  due  to  accumulation  of  carbon  dioxide  in  the  absorbing  apparatus.  The  as. 
cending  lines,  as  C  1,  form  no  proper  part  of  the  curve  but  are  due  to  addition  of  weights  by  the 
operator.  T  is  the  time  marked  every  10  seconds.  M,  revolutions  of  bicycle  crank. 


Pulse  rate 
per  minute 


10S 

j 

1 

(*ftt 

I 

3 

^ 

i 

~^~~ 

r^j 

f-U2 

<Y, 

rVS 

A> 

W 

C 

E 

| 

CMS 

r 

_^  11 

1  *5 

I 

ju 

2  ft 

1 

\f 

-"Xi 

f 

21 

/ 

1— 

\> 

(.4. 

/ 

\r 

O  7 

fin 

j 

1 

: 

0             J, 

\4 

h( 

FIGURES. —  lotted  curves  of  pulse  rate  and  of  carbon  dioxide  exc-etioti  from  same 
experiment  as  figure  7.  Broken  line,  pulse  rate;  solid  line,  carbon  dioxide  excretion. 
Ordinates  give  pulse  rate  per  minute  and  grams  of  carbon  dioxide  per  minute. 

2.     Results. 

This  figure  shows  in  a  general  way,  the  effect  of  the  work  on  the 
excretion  of  carbon  dioxide.  Beginning  at  the  left,  the  nearly  straight 
slanting  line,  A.B.,  drawn  by  the  writing  lever  of  the  chemograph  indi- 
cates the  rate  of  excretion  during  rest.  Then  when  work  begins,  the  in- 
creased slant  of  B.  C.  indicates-  an  increased  excretion,  and  this  increase 
continues  for  about  two  minutes.  From  this  time  to  the  end  of  the  work- 
ing period  the  slant  of  the  line  remains  about  the  same,  indicating  uni- 
form excretion  of  carbon  dioxide.  As  soon  as  work  stops  there  is  an 
immediate  change  in  the  slant  D.  E.,  showing  the  diminished  excre- 
tion. 

A  more  accurate  idea  of  the  changes  in  question  can  be  obtained 
from  Pig.  8,  which  was  obtained  frcm  the  record  of  Pig.  7,  by  careful 
measurements  and  plotting.  This  figure  also  contains  the  plotted 
curve  of  pulse  rate.  The  pulse  curve  shovs  plainly  a  rapid  primary 
rise,  a.  b.;  a  plateau,  b.  c.;  and  a  slow  secondary  rise.  The  curve  of  car- 
bon dioxide  rises  rather  rapidly  during  the  first  two  minutes,  which 
Incudes  the  period  of  rapid  rise  of  pulse  rate  and  a  part  of  the  plateau. 
During  the  remainder  of  the  working  period  tne  rate  of  excretion  is 
seen  to  be  practically  constant,  2ia  although  the  pulse  rate  is  rising 
for  the  latter  half  of  the  time.  On  cessation  of  work  the  excretion 
diminishes,  until  at  the  end  of  two  minutes  it  has  returned  to  practi- 
cally the  original  rate.  At  the  same  time  the  pulse  rate,  although 
falling  rapidly  at  first  (de)  is  oscillating  about  a  rate  (ef)  20  per  cent 
above  the  normal. 

(c)  Discussion  of  Results: 

A  comparison  of  the  curves  of  pulse  rate  and  carbon  dioxide  then, 
shows  that  the  primary  rise  of  pulse  frequency  coincides  in  time  ap- 
proximately with  the  rise  in  excretion  of  carbon  dioxide,  and  the  same 
can  be  said  of  the  corresponding  fall.  The  short  latent  period  of  the 
pulse  shows,  as  has  been  stated  by  Bowenf,  that  if  the  increased  pro- 


tloc.  cit. 


-46- 


duction  of  carbon  dioxide  is  in  any  way  responsible,  even  in  part,  for 
the  change  in  pulse  rate  when  work  begins,  the  influence  must  be 
brought  to  bear  through  nervous  channels,  rather  than  as  a  direct  ef- 
fect of  the  gas  upon  the  heart  itself  or  upon  the  cardiac  centers.  There 
seems  to  be  no  reason  why  the  prompt  increase  in  heart  action  may 
not  be  due  in  part  at  least  to  sensory  impulses  arising  in  the  muscles 
as  a  result  of  the  waste  products  suddenly  set  free  there  as  advocated 
by  Anthanasiu38. 

The  results,  obtained,  then,  show  no  evidence  of  any  relation  of 
cause  and  effect  between  the  production  of  carbon  dioxide,  and  the  sec- 
ondary rise  in  pulse  rate.  In  Fig.  8  it  is  seen  that  the  excretion  of 
carbon  dioxide  is  constant  during  the  entire  period  of  the  secondary 
rise  of  pulse  rate,  while  the  secondary  fall  of  pulse  rate  during  recovery 
is  continued  after  the  rate  of  excretion  of  carbon  dioxide  has  returned 
to  the  normal.  The  lack  of  correspondence  in  the  two  curves  practical- 
ly amounts  to  a  demonstration  that  the  secondary  changes  in  pulse  rate 
have  nothing  to  do  with  the  production  of  carbon  dioxide  and  its  elim- 
ination from  the  system. 


VII.  THE  LATENT  PERIOD  OF  CARBON  DIOXIDE  EXCRETION 


Method: 

A  number  of  experiments  were  made  to  determine  how  soon  after 
work  begins  the  increase  in  production  of  carbon  dioxide  begins  to  show 
itself  in  the  expired  air.  Fig.  9  shows  a  group  of  records  taken  in  the 
course  of  these  experiments.  The  procedure  is  as  follows:  The  subject, 
sitting  quietly  on  the  bicycle,  breathes  into  the  apparatus  for  about 
30  seconds,  the  rate  of  excretion  of  carbon  dioxide  being  recorded 
on  the  drum,  giving  the  line  m.  n.  in  curve  A.  He  then 
begins  driving  the  bicycle,  the  time  of  starting  being  accurately  in- 
dicated by  marker  M.  The  experiment  continues  only  long  enough  to 
show  a  definite  increase  in  the  excretion  of  carbon  dioxide  resulting 
from  the  work.'  After  fixing  the  record  in  shellac,  the  point  n  on  the 
curve  of  carbon  dioxide,  where  the  line  first  changes  its  direction  as 
the  result  of  the  work,  is  revolved  to  the  base  line  with  a  radius  equal 
tc  the  length  of  the  long  arm  of  the  writing  lever,  so  as  to  avoid  error 
due  to  rotation  of  the  lever  on  its  axis.  Now  the  number  of  seconds 
between  the  beginning  of  work  and  the  resulting  change  in  excretion  of 
carbon  dioxide  can  be  readily  obtained  from  the  time  record,  T. 

To  find  the  result  desired  we  must  deduct  from  the  time  found  in 
the  manner  just  described,  the  time  required  for  the  passage  of  the  ex- 
haled air  from  the  mouth  and  nostrils,  through  the  mask  and  connect- 
ing tubes  to  the  chemograph,  and  sufficient  additional  time  to  collect  in 
the  soda-lime  enough  carbon  dioxide  to  overcome  the  inertia  of  the  bal- 
ance. The  time  to  be  deducted  is  found  as  follows:  While  sitting 

—47— 


,81 


*l=j 

C  o  LT 


—48— 


quietly  upon  the  bicycle,  with  the  record  in  progress,  the  subject  holds 
his  breath  for  several  seconds.  The  result  is  shown  in  Curve  C  of 
Fig.  9.  The  pneumograph  curve  at  the  top  of  the  record  shows  when 
the  breath  is  held.  Scon  the  lever  point  which  records  the  movement 
of  the  balance  changes  its  direction,  finally  writing  the  horizontal  line 
r  V.  When  the  subject  begins  to  breathe  again  the  pneumograph 
curve  shows  the  exact  moment  of  the  first  expiration,  and  the  time  from 
this  point  to  the  point  V,  where  the  carbon  dioxide  lever  first  begins  to 
fall  again,  is  the  time  of  delay  due  to  the  apparatus.  Prom  a  large 
number  of  tests  this  time  was  found  to  be  close  to  6  seconds.  Since 
this  delay  depends  upon  the  rate  at  which  air  is  drawn  through  the 
apparatus  by  the  suction  pump,  all  of  the  experiments  on  latent  period 
were  made  with  the  air  moving  at  the  uniform  rate  of  20  litres  per  min- 
ute. 


2.     Results. 

Making  the  deduction  of  6  seconds  in  the  case  in  curve  A  of  Pig. 
9,  values  for  the  latent  period  were  obtained  varying  all  the  way  from 
3  to  14  seconds.  Now  few  of  these  results  are  long  enough  to  corre- 
spond with  the  time  required  for  the  carbon  dioxide  formed  in  the  mus- 
cles at  the  time  of  the  first  muscular  contraction  to  reach  the  outside 
air.  It  must  first  diffuse  into  the  blood  from  the  tissues  where  it  is 
formed,  then  traverse  the  venous  half  of  the  systemic  circulation,  the 
right  side  of  the  heart,  and  the  arterial  half  of  the  pulmonary  circula- 
tion, and  finally  diffuse  into  the  air  of  the  alveoli  before  any  of  it  can 
appear  in  the  breath.  From  the  latest  conclusions  of  Stewart  and  oth- 
ers who  are  considered  as  authorities  on  the  time  of  the  circulation,  it 
appears  that  from  15  to  20  seconds  is  the  least  possible  time  for  the 
blood  to  travel  this  distance,  to  say  nothing  of  the  diffusion  time.  We 
must  evidently  account  for  the  shortness  of  the  latent  period  thus 
found. 

Careful  study  of  the  matter  finally  led  to  the  conclusion  that  the 
sudden  change  in  rate  of  excretion  of  carbon  dioxide  on  beginning 
work  was  due  primarily  to  a  better  ventilation  of  the  lungs  while  the 
continuation  of  the  fall  was  due  to  the  ventilation  of  the  blood  and  tis- 
sues as  well.  "l 

A  recognition  of  this  fact  led  to  the  following  modification  of  the 
methods  employed  in  the  determination  of  the  latent  period  of  carbon 
dioxide  excretion. 

After  the  "normal"  rate  of  excretion  had  been  obtained  (A  B,  Fig. 
9),  the  subject  began  forced  breathing  at  a  predetermined  rate,  contin- 
uing this  for  a  minute  or  so  until  the  curve  of  carbon  dioxide  had  ap- 

—49— 


parently  assumed  its  permanent  direction.  At  this  point,  at  a  signal 
from  the  experimenter,  the  subject  began  to  drive  the  bicycle  as  in  the? 
preceding  experiments. 

Curve  B  of  Fig.  9  shows  the  result  in  one  instance.  The  effect  of 
the  increased  respiration  is  clearly  marked,  the  new  rate  of  excretion 
qr  being  sharply  denned  from  the  normal  rate  (pq)  preceding  it.  The 
further  increase  on  beginning  work  is  not  so  prompt  in  its  appearance 
rnd  comes  on  more  gradually,  reaching  its  maximum  after  a  minute  or 
more,  depending  on  the  work.  In  these  experiments  the  latent  period 
of  increase  due  to  the  work  was  from  seventeen  to  twenty-two  sec- 
onds. It  is  evident  that  as  the  latent  period  will  vary  with  the  rapidity 
of  the  circulation,  the  rapidity  of  diffusion,  and  the  rate  of  work,  a 
more  definite  figure  is  not  to  be  expected. 

Shortly  after  the  publication  of  these  results  by  Bowen  and  the 
writer,  a  communication  was  received  from  Prof.  N.  Zuntz,  calling  at- 
tention to  the  gradual  character  of  the  change  in  rate  of  excretion  of 
carbon  dioxide  after  the  beginning  of  work  (as  already  mentioned) 
and  kindly  suggesting  a  modification  of  the  method  of  carrying  out 
the  latent-period  experiments.  According  to  Prof.  Zuntz,  if  the  forced 
breathing  were  continued  for  -five  minutes  instead  of  one  minute,  as  al- 
ready stated,  the  blood  and  tissues  would  become  thoroughly  ventilated; 
the  direction  of  the  curve  of  carbon  dioxide  would  become  parallel  to 
that  before  forced  breathing  began;  and  furthermore,  with  the  begin- 
ning of  work,  the  carbon  dioxide  curve,  after  the  latent  period  of 
twenty  seconds,  would  change  much  more  sharply  than  it  did  in  the 
published  reocrd.  The  writer  accordingly  made  a  series  of  experi- 
ments in  which  the  forced  breathing  was  continued  for  from  five  to 
seven  minutes  before  bicycle  work  has  begun. 

The  results  of  one  of  these  experiments  are  seen  in  Figure  10  in 
which  A  is  the  pneumograph  record,  Pqrs  the  carbon  dioxide  curve, 
T  the  chronograph  record,  and  M  the  bicycle  record.  The  line  Pq' 
as  in  the  previous  paper,3  represents  the  rate  of  excretion  before  the 

beginning  of  forced  breathing;  the  line  Pqq'q"r  (broken  by  the  arrest- 
ing of  the  beam  and  the  addition  of  four  gram  weights)  represents 
the  curve  of  carbon  dioxide  during  forced  breathing;  r  is  the  position 
on  the  curve  of  the  carbon-dioxide-writing  lever  at  the  instant  when 
work  was  begun;  and  s  is  the  point  where  the  curve  changes  as  a  re- 
sult of  the  work. 

This  research  was  conducted  on  two  subjects.  It  was  found  very 
difficult  to  maintain  respiration  of  uniform  depth  for  five  minutes, 
since  there  is  a  decided  tendency  to  make  the  respiration  shallower. 
Indeed,  notwithstanding  the  great  care  on  the  part  of  the  subject,  the 

3Higley  and  Bowen:  Loc.  cit. 

—50— 


pneumograph  record  indicated,  in  some  cases,  a  lessened  depth  of  res- 
piration toward  the  end  of  the  forced  respiration  period. 

In  the  case  of  one  subject  the  curve  for  rate  of  excretion  of  carbon 
dioxide  returned,  during  the  period  of  forced  respiration,  practically 
to  the  original  value.  With  the  other  subject  the  return  was  less  per- 
perfect.  It  would  seem  that  as  a  result  of  the  additional  work  of 
the  respiratory  organs  a  return  of  the  rate  of  excretion  to  the  value 
during  normal  respiration  could  not  be  expected. 

While,  therefore,  the  writer  is  able  to  confirm  Prof.  Zuntz's  predic- 
tion regarding  the  sharpness  of  the  change,  as  a  result  of  work,  in  the 
curve  of  carbon  dioxide  after  continued  forced  respiration,  he  can  only 
confirm  in  part  Prof.  Zuntz's  prediction  on  the  return  of  the  curve 
during  forced  respiration,  to  the  direction  which  it  had  before  forced 
respiration  was  begun. 


'i'7-  i,  '-A. 

' 


-51— 


CONCLUSIONS 

1.  The  problem  of  finding  the  changes  in  rate  of  excretion  of  car- 
bon 'dioxide  resulting  from  muscular  work  and  other  causes  is  practi- 
cally solved  by  the  method  used  in  this  research. 

2.  The  latent  period  of  increase  in  excretion  of  carbon  dioxide 
from  the  lungs  in  case  of  beginning  work  is  approximately  twenty  sec- 
onds, and  the  increase  reaches  its  maximum  in  about  two  minutes. 

3.  The  rate  of  excretion  of  carbon  dioxide  from  the  lungs  is  prac- 
tically uniform  from  minute  to  minute  during  uniform  muscular  work, 
after  the  blood  has  had  time  to  take  part  fully  in  the  process  of  elim- 
ination. 

4.  Upon  cessation  of  work  the  excretion  of  carbon  dioxide  de- 
creases to  the  normal  amount  in  about  the  time  occupied  by  its  in- 
crease, and  after  a  like  latent  period. 

5.  The  results  obtained  show  no  indication  of  any  connection  of 
cause  and  effect  between  the  production  and  elimination  of  carbon  di- 
oxide and  the  secondary  rise  of  pulse  rate. 


GENERAL  SUMMARY 

1.  In  the  balance-chemograph  we  have  an  apparatus  which  will  oe 
of  service  in  a  study  of  the  rate  of  change  of  a  number  of  chemical 
reactions. 

2.  The  respiration  apparatus  of  which  the  chemograph  forms  a 
part  can  be  employed  with  advantage  in  a  study  of  the  character  of 
all  important  changes  in  the  rate  of  excretion  of  carbon  dioxide  from 
the  lungs;  furthermore,  with  this  apparatus  the  analyses  and  calcula- 
tions that  are  necessary  in  experiments  on  the  respiration,  are  greatly 
simplified. 

3.  The  average  carbon  dioxide  excretion  per  kilogram  of  body 
weight  per  minute  in  the  case  of  24  normal  subjects,  at  a  time  averag- 
ing four  hours  after  the  midday  meal  was  .0063  grams.      This    agrees 
well  with  values  obtained  by  Johannsen  and  Magnus-Levy. 

4.  The  daily  curve  of  metabolism  is  affected  by  the  time  of  tak- 
ing the  heartiest  meal.    Indigestion,  catarrhal  infection  and  thorough 
athletic  training  increased  the  rate  of  excretion  and  the  presence  in  the 
body  of  the  subject  of  a  large  amount  of  adipose  tissue  diminished  the 
rate  of  excretion. 

5.  A  series  of  experiments  made  daily,  morning,  noon  and  even- 
ing,  for  five  weeks,  seems  to  show  that  with  some  subjects  the  carbon 
dioxide  excretion  varies  with  the  barometric  height.     This  result  is 
in  harmony  with  results  obtained  by  Lombard  on  the  effect  of  barom- 
etric changes  on  muscular  endurance. 


6.  By  the  use  of  the  respiration  apparatus  described  in  this  paper 
the  rate  of  change  of  carbon  dioxide  excretion  from  a  condition     of 
rest  through  a  period  of  uniform  muscular  work  and  the  period  of  re- 
covery  has   been   worked   out.     This   curve   is   markedly   different   at 
important  points  from  the  corresponding  pulse  curve  as  worked  out  by 
Bowen.     The  secondary  rise  in  the  pulse  rate  is  not  due  to  the  pres- 
ence of  an  increased  amount  of  carbon  dioxide  in  the  blood. 

7.  The  latent  period  of  carbon  dioxide  excretion  as  a  result  of 
vigorous  work  is  about  20  seconds. 

8.  After  a  period  of  forced  respiration  lasting  five  minutes,  the 
curve  of  excretion  of  carbon  dioxide  nearly  returns  to  the  direction 
which  it  had  before  forced  respiration  began;  if  now  vigorous  muscular 
work  be  begun,  the  curve  of  excretion  of  carbon  dioxide  shows  a  much 
more  sharp  turn  than  in  the  case  where  the  period  of  forced  breathing 
is  much  more  brief. 


BIBLIOGRAPHY 

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